diff --git a/.travis.yml b/.travis.yml
index acd989ec7e..84179b87b9 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -24,80 +24,97 @@ env:
     - secure: "N9/qBUT5CqfC7KQBDy5mIWZcGNuUJk3e/qmKJpotWYV+zwOI4GghJsRce6nFnlRiwl65l5oBEcvf3+sBvUfbZqh7U0MdHpw2tHhr2FSCmMB3bkvARZblh9M37f4da9G9VmRkqnyBM5G5TImXtoq4dusvNWKvLW0qETciaipq7ws="
 
 git:
+  # We need a deep clone so that we can compute the age of the files using their git history.
   depth: 10000
 
 install:
-  - export IRIS_TEST_DATA_REF="2f3a6bcf25f81bd152b3d66223394074c9069a96"
-  - export IRIS_TEST_DATA_SUFFIX=$(echo "${IRIS_TEST_DATA_REF}" | sed "s/^v//")
+  - >
+    export IRIS_TEST_DATA_REF="2f3a6bcf25f81bd152b3d66223394074c9069a96";
+    export IRIS_TEST_DATA_SUFFIX=$(echo "${IRIS_TEST_DATA_REF}" | sed "s/^v//");
 
   # Install miniconda
   # -----------------
-  - export CONDA_BASE=https://repo.continuum.io/miniconda/Miniconda
-  - if [[ "$TRAVIS_PYTHON_VERSION" == 2* ]]; then
-      wget ${CONDA_BASE}2-latest-Linux-x86_64.sh -O miniconda.sh;
+  - >
+    echo 'Installing miniconda';
+    export CONDA_BASE=https://repo.continuum.io/miniconda/Miniconda;
+    if [[ "$TRAVIS_PYTHON_VERSION" == 2* ]]; then
+      wget --quiet ${CONDA_BASE}2-latest-Linux-x86_64.sh -O miniconda.sh;
     else
-      wget ${CONDA_BASE}3-latest-Linux-x86_64.sh -O miniconda.sh;
-    fi
-  - bash miniconda.sh -b -p $HOME/miniconda
-  - export PATH="$HOME/miniconda/bin:$PATH"
+      wget --quiet ${CONDA_BASE}3-latest-Linux-x86_64.sh -O miniconda.sh;
+    fi;
+    bash miniconda.sh -b -p $HOME/miniconda;
+    export PATH="$HOME/miniconda/bin:$PATH";
 
   # Create the basic testing environment
   # ------------------------------------
   # Explicitly add defaults channel, see https://github.com/conda/conda/issues/2675
-  - conda config --add channels defaults
-  - conda config --set always_yes yes --set changeps1 no
-  - conda config --set show_channel_urls True
-  - conda update --quiet conda
-  - ENV_NAME='test-environment'
-  - conda create --quiet -n $ENV_NAME python=$TRAVIS_PYTHON_VERSION
-  - source activate $ENV_NAME
+  - >
+    echo 'Configure conda and create an environment';
+    conda config --set always_yes yes --set changeps1 no;
+    conda config --set show_channel_urls True;
+    conda config --add channels conda-forge;
+    conda update --quiet conda;
+    ENV_NAME='test-environment';
+    conda create --quiet -n $ENV_NAME python=$TRAVIS_PYTHON_VERSION pip;
+    source activate $ENV_NAME;
 
   # Customise the testing environment
   # ---------------------------------
-  - conda config --add channels conda-forge
-  - if [[ "$TEST_MINIMAL" == true ]]; then
-      conda install --quiet --file minimal-conda-requirements.txt;
-    else
-      if [[ "$TRAVIS_PYTHON_VERSION" == 3* ]]; then
-        sed -e '/esmpy/d' -e 's/#.\+$//' conda-requirements.txt | xargs conda install --quiet;
-      else
-        conda install --quiet --file conda-requirements.txt;
-      fi
-    fi
-
-  # JUST FOR NOW : Install latest version of iris-grib.
-  # TODO : remove when this release is available on conda-forge.
-  - if [[ "$TEST_MINIMAL" != true ]]; then
-        pip install git+https://github.com/SciTools/iris-grib.git@v0.11.0 ;
-    fi
+  - >
+    echo 'Install Iris dependencies';
+    CONDA_REQS_FLAGS="";
+    CONDA_REQS_GROUPS="test";
+    if [[ "$TRAVIS_PYTHON_VERSION" == 2* ]]; then
+        CONDA_REQS_FLAGS="${CONDA_REQS_FLAGS} --py2";
+    fi;
+    if [[ "$TEST_MINIMAL" != true ]]; then
+        CONDA_REQS_GROUPS="${CONDA_REQS_GROUPS} all";
+    fi;
+    if [[ "${TEST_TARGET}" == 'doctest' ]]; then
+        CONDA_REQS_GROUPS="${CONDA_REQS_GROUPS} docs";
+    fi;
+    CONDA_REQS_FILE=conda-requirements.txt;
+    python requirements/gen_conda_requirements.py ${CONDA_REQS_FLAGS} --groups ${CONDA_REQS_GROUPS} > ${CONDA_REQS_FILE};
+    cat ${CONDA_REQS_FILE};
+    conda install --quiet --file ${CONDA_REQS_FILE};
 
   - PREFIX=$HOME/miniconda/envs/$ENV_NAME
 
   # Output debug info
-  - conda list
-  - conda info -a
+  - >
+    conda list;
+    conda info -a;
 
 # Pre-load Natural Earth data to avoid multiple, overlapping downloads.
 # i.e. There should be no DownloadWarning reports in the log.
   - python -c 'import cartopy; cartopy.io.shapereader.natural_earth()'
 
 # iris test data
-  - if [[ "$TEST_MINIMAL" != true ]]; then
-      wget -O iris-test-data.zip https://github.com/SciTools/iris-test-data/archive/${IRIS_TEST_DATA_REF}.zip;
+  - >
+    if [[ "$TEST_MINIMAL" != true ]]; then
+      wget --quiet -O iris-test-data.zip https://github.com/SciTools/iris-test-data/archive/${IRIS_TEST_DATA_REF}.zip;
       unzip -q iris-test-data.zip;
-      ln -s $(pwd)/iris-test-data-${IRIS_TEST_DATA_SUFFIX} iris-test-data;
+      mv "iris-test-data-${IRIS_TEST_DATA_SUFFIX}" iris-test-data;
     fi
 
 # set config paths
-  - SITE_CFG=lib/iris/etc/site.cfg
-  - echo "[Resources]" > $SITE_CFG
-  - echo "test_data_dir = $(pwd)/iris-test-data/test_data" >> $SITE_CFG
-  - echo "doc_dir = $(pwd)/docs/iris" >> $SITE_CFG
-  - echo "[System]" >> $SITE_CFG
-  - echo "udunits2_path = $PREFIX/lib/libudunits2.so" >> $SITE_CFG
+  - >
+    SITE_CFG=lib/iris/etc/site.cfg;
+    echo "[Resources]" > $SITE_CFG;
+    echo "test_data_dir = $(pwd)/iris-test-data/test_data" >> $SITE_CFG;
+    echo "doc_dir = $(pwd)/docs/iris" >> $SITE_CFG;
+    echo "[System]" >> $SITE_CFG;
+    echo "udunits2_path = $PREFIX/lib/libudunits2.so" >> $SITE_CFG;
 
   - python setup.py --quiet install
 
+  # JUST FOR NOW : Install latest version of iris-grib.
+  # TODO : remove when iris doesn't do an integration test requiring iris-grib.
+  - if [[ "$TEST_MINIMAL" != true && ${TRAVIS_PYTHON_VERSION} == 2* ]]; then
+        conda install python-ecmwf_grib;
+        pip install git+https://github.com/SciTools/iris-grib.git@v0.11.0;
+    fi
+
 script:
   - if [[ $TEST_TARGET == 'default' ]]; then
       python -m iris.tests.runner --default-tests --system-tests --print-failed-images --num-processors=3;
diff --git a/conda-requirements.txt b/conda-requirements.txt
deleted file mode 100644
index 9ada018681..0000000000
--- a/conda-requirements.txt
+++ /dev/null
@@ -1,38 +0,0 @@
-# Use this file to create a conda environment using:
-# conda create -n <name> --file conda-requirements.txt
-
-# Mandatory dependencies
-cartopy
-matplotlib<1.9
-netcdf4
-numpy
-pyke
-udunits2
-cf_units
-dask>=0.15.0
-
-# Iris build dependencies
-setuptools
-
-# Iris testing/documentation dependencies
-mock
-nose
-pep8
-sphinx
-iris-sample-data
-filelock
-imagehash
-requests
-
-# Optional iris dependencies
-esmpy>=7.0
-gdal
-libmo_unpack
-mo_pack
-nc_time_axis
-pandas
-python-stratify
-pyugrid
-
-# Iris extensions (i.e. key tools that depend on Iris)
-# iris_grib>=0.12
diff --git a/minimal-conda-requirements.txt b/minimal-conda-requirements.txt
deleted file mode 100644
index 4ba37a39c6..0000000000
--- a/minimal-conda-requirements.txt
+++ /dev/null
@@ -1,27 +0,0 @@
-# Use this file to create a conda environment using:
-# conda create -n <name> --file minimal-conda-requirements.txt
-
-# Mandatory dependencies
-cartopy
-matplotlib<1.9
-netcdf4
-numpy
-pyke
-udunits2
-cf_units
-dask>=0.15.0
-
-# Iris build dependencies
-setuptools
-
-# Iris testing/documentation dependencies
-mock
-nose
-pep8
-sphinx
-filelock
-imagehash
-requests
-
-# Optional iris dependencies
-mo_pack
diff --git a/requirements/all.txt b/requirements/all.txt
new file mode 100644
index 0000000000..eb0354fc80
--- /dev/null
+++ b/requirements/all.txt
@@ -0,0 +1,17 @@
+# Dependencies for a feature complete installation
+# ------------------------------------------------
+
+# esmpy regridding not available through pip.
+#conda: esmpy>=7.0  (only python=2)
+gdal
+mo_pack
+nc_time_axis
+pandas
+stratify  #conda: python-stratify
+pyugrid
+
+#conda: graphviz
+
+# Iris sample data is not available through pip. It can be installed from
+# https://github.com/SciTools/iris-sample-data/archive/master.zip
+#conda: iris-sample-data
diff --git a/requirements/core.txt b/requirements/core.txt
new file mode 100644
index 0000000000..d2540da9f1
--- /dev/null
+++ b/requirements/core.txt
@@ -0,0 +1,12 @@
+# Absolute minimal dependencies for iris
+# --------------------------------------
+
+# Without these, iris won't even import.
+
+cartopy
+matplotlib<1.9
+netcdf4
+numpy
+# pyke (not pip installable)  #conda: pyke
+cf_units
+dask>=0.15.0
diff --git a/requirements/docs.txt b/requirements/docs.txt
new file mode 100644
index 0000000000..6966869c70
--- /dev/null
+++ b/requirements/docs.txt
@@ -0,0 +1 @@
+sphinx
diff --git a/requirements/extensions.txt b/requirements/extensions.txt
new file mode 100644
index 0000000000..64a28e91f2
--- /dev/null
+++ b/requirements/extensions.txt
@@ -0,0 +1,8 @@
+# Iris extensions (i.e. key tools that depend on Iris)
+# ----------------------------------------------------
+
+# Note: pip can handle the circularity of these extensions, but conda will
+# struggle. To install these extensions, ensure iris[core] has been installed
+# first.
+
+iris_grib;python_version<"3"  #conda:
diff --git a/requirements/gen_conda_requirements.py b/requirements/gen_conda_requirements.py
new file mode 100644
index 0000000000..a6a5fd84aa
--- /dev/null
+++ b/requirements/gen_conda_requirements.py
@@ -0,0 +1,91 @@
+# (C) British Crown Copyright 2017, Met Office
+#
+# This file is part of Iris.
+#
+# Iris is free software: you can redistribute it and/or modify it under
+# the terms of the GNU Lesser General Public License as published by the
+# Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Iris is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with Iris.  If not, see <http://www.gnu.org/licenses/>.
+
+import argparse
+import os.path
+
+
+REQS_DIR = os.path.dirname(__file__)
+CONDA_PATTERN = '#conda:'
+
+
+def read_conda_reqs(fname, options):
+    lines = []
+    with open(fname, 'r') as fh:
+        for line in fh:
+            line = line.strip()
+            if '#conda:' in line:
+                line_start = line.index(CONDA_PATTERN) + len(CONDA_PATTERN)
+                line = line[line_start:].strip()
+                if 'only python=2' in line:
+                    if 'python=2' in options:
+                        line = line.replace('(only python=2)', '')
+                        lines.append(line)
+                    else:
+                        continue
+                else:
+                    lines.append(line)
+            else:
+                lines.append(line)
+    return lines
+
+
+def compute_requirements(requirement_names=('core', ), options=None):
+    conda_reqs_lines = []
+
+    if 'python=2' in options:
+        conda_reqs_lines.append('python=2.*')
+    else:
+        conda_reqs_lines.append('# Python 3 conda configuration')
+
+    for req_name in requirement_names:
+        fname = os.path.join(REQS_DIR, '{}.txt'.format(req_name))
+        if not os.path.exists(fname):
+            raise RuntimeError('Unable to find the requirements file for {} '
+                               'in {}'.format(req_name, fname))
+        conda_reqs_lines.extend(read_conda_reqs(fname, options))
+        conda_reqs_lines.append('')
+
+    return conda_reqs_lines
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--verbosity", help="increase output verbosity")
+    parser.add_argument(
+            "--groups", nargs='*', default=[],
+            help=("Gather requirements for these given named groups "
+                  "(as found in the requirements/ folder)"))
+    parser.add_argument(
+            "--py2", action="store_true",
+            help="Build the conda requirements for a python 2 installation")
+
+    args = parser.parse_args()
+
+    requirement_names = args.groups
+    requirement_names.insert(0, 'core')
+    requirement_names.insert(0, 'setup')
+
+    options = []
+    if args.py2:
+        options.append('python=2')
+
+    print('\n'.join(compute_requirements(requirement_names, options)))
+
+
+if __name__ == '__main__':
+    main()
diff --git a/requirements/setup.txt b/requirements/setup.txt
new file mode 100644
index 0000000000..552f54318c
--- /dev/null
+++ b/requirements/setup.txt
@@ -0,0 +1,6 @@
+# Dependencies necessary to run setup.py of iris
+# ----------------------------------------------
+
+setuptools
+# pyke (not pip installable)  #conda: pyke
+six
diff --git a/requirements/test.txt b/requirements/test.txt
new file mode 100644
index 0000000000..26a00bcacc
--- /dev/null
+++ b/requirements/test.txt
@@ -0,0 +1,9 @@
+# Dependencies needed to run the iris tests
+#------------------------------------------
+
+mock
+nose
+pep8
+filelock
+imagehash
+requests
diff --git a/setup.py b/setup.py
index 702e59eb82..2b7787effc 100644
--- a/setup.py
+++ b/setup.py
@@ -1,14 +1,13 @@
 from __future__ import print_function
 
 from contextlib import contextmanager
-from distutils.core import Command
 from distutils.util import convert_path
 import os
 from shutil import copyfile
 import sys
 import textwrap
 
-from setuptools import setup
+from setuptools import setup, Command
 from setuptools.command.develop import develop as develop_cmd
 from setuptools.command.build_py import build_py
 
@@ -68,6 +67,22 @@ def temporary_path(directory):
 with temporary_path('lib/iris/tests/runner'):
     from _runner import TestRunner  # noqa:
 
+SETUP_DIR = os.path.dirname(__file__)
+
+def pip_requirements(name):
+    fname = os.path.join(SETUP_DIR, 'requirements', '{}.txt'.format(name))
+    if not os.path.exists(fname):
+        raise RuntimeError('Unable to find the {} requirements file at {}'
+                           ''.format(name, fname))
+    reqs = []
+    with open(fname, 'r') as fh:
+        for line in fh:
+            line = line.strip()
+            if not line or line.startswith('#'):
+                continue
+            reqs.append(line)
+    return reqs
+
 
 class SetupTestRunner(TestRunner, Command):
     pass
@@ -186,8 +201,7 @@ def run(self):
 
 def extract_version():
     version = None
-    fdir = os.path.dirname(__file__)
-    fnme = os.path.join(fdir, 'lib', 'iris', '__init__.py')
+    fnme = os.path.join(SETUP_DIR, 'lib', 'iris', '__init__.py')
     with open(fnme) as fd:
         for line in fd:
             if (line.startswith('__version__')):
@@ -214,8 +228,11 @@ def extract_version():
     }
 
 
+pypi_name = 'scitools-iris'
+
+
 setup(
-    name='Iris',
+    name=pypi_name,
     version=extract_version(),
     url='http://scitools.org.uk/iris/',
     author='UK Met Office',
@@ -223,7 +240,16 @@ def extract_version():
     packages=find_package_tree('lib/iris', 'iris'),
     package_dir={'': 'lib'},
     include_package_data=True,
-    tests_require=['nose'],
     cmdclass=custom_commands,
+
     zip_safe=False,
-   )
+
+    setup_requires=pip_requirements('setup'),
+    install_requires=pip_requirements('core'),
+    tests_require=['{}[test]'.format(pypi_name)],
+    extras_require = {
+                      'test': pip_requirements('test'),
+                      'all': pip_requirements('all'),
+                      'extensions': pip_requirements('extensions'),
+                      },
+)