diff --git a/src/components/fields/ArrayField.js b/src/components/fields/ArrayField.js
index 6c59dc5ed9..901dfa43b0 100644
--- a/src/components/fields/ArrayField.js
+++ b/src/components/fields/ArrayField.js
@@ -12,6 +12,7 @@ import {
   retrieveSchema,
   toIdSchema,
   getDefaultRegistry,
+  cleanUpNonRequiredArray,
 } from "../../utils";
 
 function ArrayFieldTitle({ TitleField, idSchema, title, required }) {
@@ -202,14 +203,19 @@ class ArrayField extends Component {
 
   onAddClick = event => {
     event.preventDefault();
-    const { schema, registry, formData } = this.props;
+    const { schema, registry, required } = this.props;
     const { definitions } = registry;
+    let formData = this.props.formData;
     let itemSchema = schema.items;
     if (isFixedItems(schema) && allowAdditionalItems(schema)) {
       itemSchema = schema.additionalItems;
     }
+
     this.props.onChange(
-      [...formData, getDefaultFormState(itemSchema, undefined, definitions)],
+      [
+        ...formData,
+        getDefaultFormState(itemSchema, undefined, definitions, required),
+      ],
       { validate: false }
     );
   };
@@ -219,9 +225,18 @@ class ArrayField extends Component {
       if (event) {
         event.preventDefault();
       }
-      const { formData, onChange } = this.props;
+      const { onChange, required } = this.props;
+      let formData = this.props.formData;
+
+      // if field isn't required and doesn't contain any entries
+      // remove the whole property from formData to guarantee correct validation
+      if (!required) {
+        formData = cleanUpNonRequiredArray(formData);
+      }
       // refs #195: revalidate to ensure properly reindexing errors
-      onChange(formData.filter((_, i) => i !== index), { validate: true });
+
+      formData = formData ? formData.filter((_, i) => i !== index) : formData;
+      onChange(formData, { validate: true });
     };
   };
 
@@ -250,12 +265,13 @@ class ArrayField extends Component {
   onChangeForIndex = index => {
     return value => {
       const { formData, onChange } = this.props;
-      const newFormData = formData.map((item, i) => {
+      let newFormData = formData.map((item, i) => {
         // We need to treat undefined items as nulls to have validation.
         // See https://github.com/tdegrunt/jsonschema/issues/206
         const jsonValue = typeof value === "undefined" ? null : value;
         return index === i ? jsonValue : item;
       });
+
       onChange(newFormData, { validate: false });
     };
   };
diff --git a/src/components/fields/ObjectField.js b/src/components/fields/ObjectField.js
index ff7e2ed172..e23d850289 100644
--- a/src/components/fields/ObjectField.js
+++ b/src/components/fields/ObjectField.js
@@ -4,6 +4,7 @@ import {
   orderProperties,
   retrieveSchema,
   getDefaultRegistry,
+  cleanUpNonRequiredObject,
 } from "../../utils";
 
 class ObjectField extends Component {
@@ -26,7 +27,14 @@ class ObjectField extends Component {
 
   onPropertyChange = name => {
     return (value, options) => {
-      const newFormData = { ...this.props.formData, [name]: value };
+      const { required } = this.props;
+
+      let newFormData = { ...this.props.formData, [name]: value };
+
+      if (!required) {
+        newFormData = cleanUpNonRequiredObject(newFormData);
+      }
+
       this.props.onChange(newFormData, options);
     };
   };
diff --git a/src/utils.js b/src/utils.js
index 6d2135e636..89c32d120d 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -103,7 +103,12 @@ export function getWidget(schema, widget, registeredWidgets = {}) {
   throw new Error(`No widget "${widget}" for type "${type}"`);
 }
 
-function computeDefaults(schema, parentDefaults, definitions = {}) {
+function computeDefaults(
+  schema,
+  parentDefaults,
+  definitions = {},
+  required = false
+) {
   // Compute the defaults recursively: give highest priority to deepest nodes.
   let defaults = parentDefaults;
   if (isObject(defaults) && isObject(schema.default)) {
@@ -116,10 +121,10 @@ function computeDefaults(schema, parentDefaults, definitions = {}) {
   } else if ("$ref" in schema) {
     // Use referenced schema defaults for this node.
     const refSchema = findSchemaDefinition(schema.$ref, definitions);
-    return computeDefaults(refSchema, defaults, definitions);
+    return computeDefaults(refSchema, defaults, definitions, required);
   } else if (isFixedItems(schema)) {
     defaults = schema.items.map(itemSchema =>
-      computeDefaults(itemSchema, undefined, definitions));
+      computeDefaults(itemSchema, undefined, definitions, required));
   }
   // Not defaults defined for this node, fallback to generic typed ones.
   if (typeof defaults === "undefined") {
@@ -133,32 +138,76 @@ function computeDefaults(schema, parentDefaults, definitions = {}) {
         (acc, key) => {
           // Compute the defaults for this node, with the parent defaults we might
           // have from a previous run: defaults[key].
-          acc[key] = computeDefaults(
-            schema.properties[key],
-            (defaults || {})[key],
-            definitions
-          );
+          if (acc) {
+            acc[key] = computeDefaults(
+              schema.properties[key],
+              (defaults || {})[key],
+              definitions,
+              schema.required && schema.required.indexOf(key) > -1
+            );
+
+            if (!required) {
+              acc = cleanUpNonRequiredObject(acc);
+            }
+          }
           return acc;
         },
         {}
       );
 
     case "array":
-      if (schema.minItems) {
+      if (required && schema.minItems) {
         return new Array(schema.minItems).fill(
-          computeDefaults(schema.items, defaults, definitions)
+          computeDefaults(schema.items, defaults, definitions, required)
         );
       }
   }
   return defaults;
 }
 
-export function getDefaultFormState(_schema, formData, definitions = {}) {
+export function cleanUpNonRequiredObject(values) {
+  const cleanValues = [];
+
+  for (let key in values) {
+    if (values.hasOwnProperty(key) && typeof values[key] !== "undefined") {
+      cleanValues.push(values[key]);
+    }
+  }
+
+  if (!cleanValues.length) {
+    values = undefined;
+  }
+
+  return values;
+}
+
+export function cleanUpNonRequiredArray(values) {
+  values = values.filter(item => {
+    return item !== null && item !== undefined;
+  });
+
+  values = values.length ? values : undefined;
+
+  return values;
+}
+
+export function getDefaultFormState(
+  _schema,
+  formData,
+  definitions = {},
+  required = true
+) {
   if (!isObject(_schema)) {
     throw new Error("Invalid schema: " + _schema);
   }
+
   const schema = retrieveSchema(_schema, definitions);
-  const defaults = computeDefaults(schema, _schema.default, definitions);
+  const defaults = computeDefaults(
+    schema,
+    _schema.default,
+    definitions,
+    required
+  );
   if (typeof formData === "undefined") {
     // No form data? Use schema defaults.
     return defaults;
@@ -197,6 +246,8 @@ export function isObject(thing) {
 
 export function mergeObjects(obj1, obj2, concatArrays = false) {
   // Recursively merge deeply nested objects.
+  obj1 = obj1 || {};
+  obj2 = obj2 || {};
   var acc = Object.assign({}, obj1); // Prevent mutation of source object.
   return Object.keys(obj2).reduce(
     (acc, key) => {
diff --git a/test/ArrayField_test.js b/test/ArrayField_test.js
index d2af33113a..2476a01400 100644
--- a/test/ArrayField_test.js
+++ b/test/ArrayField_test.js
@@ -330,7 +330,7 @@ describe("ArrayField", () => {
       expect(inputs[3].id).eql("root_foo_1_baz");
     });
 
-    it("should render enough inputs with proper defaults to match minItems in schema when no formData is set", () => {
+    it("should render enough inputs with proper defaults when required to match minItems in schema when no formData is set", () => {
       const complexSchema = {
         type: "object",
         definitions: {
@@ -353,13 +353,45 @@ describe("ArrayField", () => {
             },
           },
         },
+        required: ["foo"],
       };
       let form = createFormComponent({ schema: complexSchema, formData: {} });
       let inputs = form.node.querySelectorAll("input[type=text]");
+      console.log(0, inputs[0].value);
+      console.log(1, inputs[1].value);
       expect(inputs[0].value).eql("Default name");
       expect(inputs[1].value).eql("Default name");
     });
 
+    it("should not render inputs with defaults when not required to match minItems in schema when no formData is set", () => {
+      const complexSchema = {
+        type: "object",
+        definitions: {
+          Thing: {
+            type: "object",
+            properties: {
+              name: {
+                type: "string",
+                default: "Default name",
+              },
+            },
+          },
+        },
+        properties: {
+          foo: {
+            type: "array",
+            minItems: 2,
+            items: {
+              $ref: "#/definitions/Thing",
+            },
+          },
+        },
+      };
+      let form = createFormComponent({ schema: complexSchema, formData: {} });
+      let inputs = form.node.querySelectorAll("input[type=text]");
+      expect(inputs.length).eql(0);
+    });
+
     it("should honor given formData, even when it does not meet ths minItems-requirement", () => {
       const complexSchema = {
         type: "object",
diff --git a/test/utils_test.js b/test/utils_test.js
index 586f4594a3..33c52374b5 100644
--- a/test/utils_test.js
+++ b/test/utils_test.js
@@ -43,7 +43,7 @@ describe("utils", () => {
         ).to.eql({ string: "foo" });
       });
 
-      it("should recursively map schema object default to form state", () => {
+      it("should recursively map schema object default to form state if required", () => {
         expect(
           getDefaultFormState({
             type: "object",
@@ -58,6 +58,7 @@ describe("utils", () => {
                 },
               },
             },
+            required: ["object"],
           })
         ).to.eql({ object: { string: "foo" } });
       });
@@ -79,6 +80,40 @@ describe("utils", () => {
         ).to.eql({ array: ["foo", "bar"] });
       });
 
+      it("should map schema array to undefined when no data and no defaults provided", () => {
+        expect(
+          getDefaultFormState({
+            type: "object",
+            properties: {
+              array: {
+                type: "array",
+                items: {
+                  type: "string",
+                },
+              },
+            },
+          })
+        ).to.eql({ array: undefined });
+      });
+
+      it("should map schema to undefined when not required and every property is undefined data and no defaults provided", () => {
+        expect(
+          getDefaultFormState({
+            type: "object",
+            properties: {
+              object: {
+                type: "object",
+                properties: {
+                  string: {
+                    type: "string",
+                  },
+                },
+              },
+            },
+          })
+        ).to.eql({ object: undefined });
+      });
+
       it("should recursively map schema array default to form state", () => {
         expect(
           getDefaultFormState({
@@ -161,7 +196,7 @@ describe("utils", () => {
         });
       });
 
-      it("should use parent defaults for ArrayFields", () => {
+      it("should use parent defaults for ArrayFields if required", () => {
         const schema = {
           type: "object",
           properties: {