diff --git a/README.md b/README.md
index 4167926..6339acf 100644
--- a/README.md
+++ b/README.md
@@ -81,9 +81,10 @@ This is skipped if the requested file already has an extension.
 
 ##### index
 
-By default send supports "index.html" files, to disable this
-set `false` or to supply a new index pass a string or an array
-in preferred order.
+By default send supports `index.html` files, to disable this set `false`. You
+can supply a different index file by setting it to a string or array of strings
+in the preferred order to be evaluated, or you can set it to a function that
+will process the index content response.
 
 ##### lastModified
 
@@ -229,7 +230,7 @@ var app = http.createServer(function onRequest (req, res) {
 }).listen(3000)
 ```
 
-## License 
+## License
 
 [MIT](LICENSE)
 
diff --git a/index.js b/index.js
index 81ec0b3..3982980 100644
--- a/index.js
+++ b/index.js
@@ -146,9 +146,18 @@ function SendStream (req, path, options) {
     ? normalizeList(opts.extensions, 'extensions option')
     : []
 
-  this._index = opts.index !== undefined
-    ? normalizeList(opts.index, 'index option')
-    : ['index.html']
+  switch (typeof opts.index) {
+    case 'function':
+      this._index = opts.index
+      break
+
+    case 'undefined':
+      this._index = ['index.html']
+      break
+
+    default:
+      this._index = normalizeList(opts.index, 'index option')
+  }
 
   this._lastModified = opts.lastModified !== undefined
     ? Boolean(opts.lastModified)
@@ -707,6 +716,8 @@ SendStream.prototype.sendIndex = function sendIndex (path) {
   var self = this
 
   function next (err) {
+    if (typeof self._index === 'function') return self._index(path)
+
     if (++i >= self._index.length) {
       if (err) return self.onStatError(err)
       return self.error(404)
diff --git a/package.json b/package.json
index 3a93e89..c34ce04 100644
--- a/package.json
+++ b/package.json
@@ -29,14 +29,14 @@
     "statuses": "~1.3.0"
   },
   "devDependencies": {
-    "after": "0.8.1",
-    "eslint": "2.11.1",
-    "eslint-config-standard": "5.3.1",
-    "eslint-plugin-promise": "1.3.1",
-    "eslint-plugin-standard": "1.3.2",
-    "istanbul": "0.4.3",
-    "mocha": "2.5.3",
-    "supertest": "1.1.0"
+    "after": "0.8.2",
+    "eslint": "3.4.0",
+    "eslint-config-standard": "6.0.0",
+    "eslint-plugin-promise": "2.0.1",
+    "eslint-plugin-standard": "2.0.0",
+    "istanbul": "0.4.5",
+    "mocha": "3.0.2",
+    "supertest": "2.0.0"
   },
   "files": [
     "HISTORY.md",
diff --git a/test/send.js b/test/send.js
index da101aa..173ffd3 100644
--- a/test/send.js
+++ b/test/send.js
@@ -1127,6 +1127,18 @@ describe('send(file, options)', function () {
       .expect(200, fs.readFileSync(path.join(fixtures, 'pets', 'index.html'), 'utf8'), done)
     })
 
+    it('should accept a function', function (done) {
+      var expected = '<p>tobi</p>'
+
+      function index (path) {
+        this.res.end(expected)
+      }
+
+      request(createServer({root: fixtures, index: index}))
+      .get('/pets/')
+      .expect(200, expected, done)
+    })
+
     it('should 404 if no index file found (file)', function (done) {
       request(createServer({root: fixtures, index: 'default.htm'}))
       .get('/pets/')