diff --git a/src/createIntlObject.js b/src/createIntlObject.js
index 20cd197..bc0accc 100644
--- a/src/createIntlObject.js
+++ b/src/createIntlObject.js
@@ -1,6 +1,11 @@
+import getValue from './utils/getValue';
 import formatMessage from './formatMessage';
 
-export default (intl) => ({
+function createIntlObject(intl) {
+  return {
     formatMessage: formatMessage(intl),
-    locale: intl.locale
-});
+    locale: getValue(intl, 'locale')
+  }
+}
+
+export default createIntlObject;
diff --git a/src/createMapStateToProps.js b/src/createMapStateToProps.js
index 21523fd..d650ead 100644
--- a/src/createMapStateToProps.js
+++ b/src/createMapStateToProps.js
@@ -1,14 +1,15 @@
+import getValue from './utils/getValue';
 import createIntlObject from './createIntlObject';
 import intlSelector from './intlSelector';
 
-export function createMapStateToProps(selector = intlSelector) {
+function createMapStateToProps(selector = intlSelector) {
   return (state) => {
     const intl = selector(state);
 
     return {
       intl: createIntlObject(intl),
-      key: intl.locale
-    };
+      key: getValue(intl, 'locale')
+    }
   };
 }
 
diff --git a/src/formatMessage.js b/src/formatMessage.js
index fabb051..58f8fa7 100644
--- a/src/formatMessage.js
+++ b/src/formatMessage.js
@@ -1,40 +1,22 @@
 import invariant from 'invariant';
-import get from 'lodash/get';
 import isEmpty from 'lodash/isEmpty';
 import isFunction from 'lodash/isFunction';
 
+import getMessage from './utils/getMessage';
+import getValue from './utils/getValue';
 import {LOG_PREFIX} from './constants';
 
 const ENV = process.env.NODE_ENV;
 
-function isImmutable(state) {
-  return isFunction(state.get)
-    && isFunction(state.getIn);
-}
-
-function getLocale(state) {
-  if (isImmutable(state)) {
-    return state.get('locale');
-  }
-  return state.locale;
-}
-
-function parseMessage(message, values = {}) {
+const parseMessage = (message, values = {}) => {
   if (message && isFunction(message)) {
     return message(values);
   }
   return void 0;
 }
 
-function getMessage(state, id) {
-  if (isImmutable(state)) {
-    return state.getIn(['messages', id], '');
-  }
-  return get(state, ['messages', id], '');
-}
-
 function formatMessage(state = {}) {
-  const locale = getLocale(state);
+  const locale = getValue(state, 'locale');
 
   if (!locale) {
     return () => '';
diff --git a/src/injectIntl.js b/src/injectIntl.js
index 3d7907b..650f293 100644
--- a/src/injectIntl.js
+++ b/src/injectIntl.js
@@ -2,7 +2,7 @@ import invariant from 'invariant';
 import {LOG_PREFIX} from './constants';
 import createMapStateToProps from './createMapStateToProps';
 
-export function injectIntl(
+function injectIntl(
   connect,
   mapStateToProps = createMapStateToProps()
 ) {
diff --git a/src/intlReducer.js b/src/intlReducer.js
index a07a720..11d0eab 100644
--- a/src/intlReducer.js
+++ b/src/intlReducer.js
@@ -1,22 +1,34 @@
+import isImmutable from './utils/isImmutable';
 import {UPDATE_ACTION} from './constants';
 
-export const initialState = () => ({
-  cacheDisable: false,
-  ecmaSupport: false,
-  locale: '',
-  messages: {}
-});
+function initialState() {
+  return {
+    cacheDisable: false,
+    ecmaSupport: false,
+    locale: '',
+    messages: {}
+  }
+}
+
+function setImmutable(state, payload) {
+  return state.merge(payload);
+}
 
-export function intlReducer(state = initialState(), action = {}) {
+function intlReducer(state = initialState(), action = {}) {
 
-  if (action && action.type === UPDATE_ACTION) {
-    return {
-      ...state,
-      ...action.payload
-    };
+  if (!action || action.type !== UPDATE_ACTION) {
+    return state;
   }
 
-  return state;
+  if (isImmutable(state)) {
+    return setImmutable(state, action.payload);
+  }
+
+  return {
+    ...state,
+    ...action.payload
+  }
 }
 
+export {initialState as initialState};
 export default intlReducer;
diff --git a/src/intlSelector.js b/src/intlSelector.js
index 30f4497..0c07ce9 100644
--- a/src/intlSelector.js
+++ b/src/intlSelector.js
@@ -1,5 +1,6 @@
 import MessageFormat from 'messageformat';
 import isEmpty from 'lodash/isEmpty';
+import isImmutable from './utils/isImmutable';
 
 const isIntlValid = (intl) => (
   !isEmpty(intl) && intl.locale
@@ -16,11 +17,17 @@ const compileMessages = (intl) => (
     .compile(intl.messages)
 );
 
+const getIntl = (state) => (
+  isImmutable(state.intl)
+    ? state.intl.toJS()
+    : state.intl
+);
+
 export function createIntlSelector() {
   let cache = {};
 
   return (state = {}) => {
-    const {intl} = state;
+    const intl = getIntl(state);
 
     if (!isIntlValid(intl)) {
       cache = {}
diff --git a/src/updateIntl.js b/src/updateIntl.js
index 74deb07..fe72d8f 100644
--- a/src/updateIntl.js
+++ b/src/updateIntl.js
@@ -4,11 +4,11 @@ import {initialState} from './intlReducer';
 
 const ACCEPTABLE_KEYS = Object.keys(initialState());
 
-export function updateIntl(keys = {}) {
+function updateIntl(keys = {}) {
   return {
     type: UPDATE_ACTION,
     payload: pick(keys, ACCEPTABLE_KEYS)
-  };
+  }
 }
 
 export default updateIntl;
diff --git a/src/utils/getMessage.js b/src/utils/getMessage.js
new file mode 100644
index 0000000..b3c16d2
--- /dev/null
+++ b/src/utils/getMessage.js
@@ -0,0 +1,11 @@
+import get from 'lodash/get';
+import isImmutable from './isImmutable';
+
+function getMessage(state, id) {
+  if (isImmutable(state)) {
+    return state.getIn(['messages', id], '');
+  }
+  return get(state, ['messages', id], '');
+}
+
+export default getMessage;
diff --git a/src/utils/getValue.js b/src/utils/getValue.js
new file mode 100644
index 0000000..be649bc
--- /dev/null
+++ b/src/utils/getValue.js
@@ -0,0 +1,11 @@
+import get from 'lodash/get';
+import isImmutable from './isImmutable';
+
+function getValue(state, value) {
+  if (isImmutable(state)) {
+    return state.get(value);
+  }
+  return get(state, value);
+}
+
+export default getValue;
diff --git a/src/utils/isImmutable.js b/src/utils/isImmutable.js
new file mode 100644
index 0000000..ca025d3
--- /dev/null
+++ b/src/utils/isImmutable.js
@@ -0,0 +1,7 @@
+import isFunction from 'lodash/isFunction';
+
+function isImmutable(state = {}) {
+  return isFunction(state.toJS);
+}
+
+export default isImmutable;
diff --git a/tests/intlReducer.spec.js b/tests/intlReducer.spec.js
index c73803f..8233273 100644
--- a/tests/intlReducer.spec.js
+++ b/tests/intlReducer.spec.js
@@ -1,4 +1,5 @@
 import {expect} from 'chai';
+import {fromJS} from 'immutable';
 import {UPDATE_ACTION} from '../src/constants';
 import intlReducer, {initialState} from '../src/intlReducer';
 
@@ -27,6 +28,16 @@ describe('intlReducer', function () {
     expect(result).to.deep.eql(expected);
   });
 
+  it('updates state even if immutable', function () {
+    const action = {
+      type: UPDATE_ACTION,
+      payload: getUpdatePayload()
+    }
+    const expected = fromJS(getUpdatePayload());
+    const result = intlReducer(fromJS(initialState()), action);
+    expect(result.toJS()).to.deep.equal(expected.toJS());
+  });
+
   function getUpdatePayload() {
     return {
       cacheDisable: false,
diff --git a/tests/intlSelector.spec.js b/tests/intlSelector.spec.js
index 5755b46..e28f703 100644
--- a/tests/intlSelector.spec.js
+++ b/tests/intlSelector.spec.js
@@ -1,4 +1,5 @@
 import {expect} from 'chai';
+import {fromJS} from 'immutable';
 import mockMessageFormat from './mocks/messageformat';
 import defaultIntlSelector, {createIntlSelector} from '../src/intlSelector';
 
@@ -36,6 +37,30 @@ describe('intlSelector', function () {
     expect(round2.messages.alternate).to.be.undefined;
   });
 
+  it('returns empty object when unable to locale intl even when state is immutable', function () {
+    const intlSelector = createIntlSelector();
+    const result = intlSelector({
+      intl: fromJS({})
+    });
+    expect(result).to.be.empty;
+  });
+
+  it('returns cache when cache intl and reducer intl is the same even when state is immutable.', function () {
+    const intlSelector = createIntlSelector();
+
+    let state1 = getState();
+    state1.intl = fromJS(state1.intl);
+    const round1 = intlSelector(state1);
+    expect(round1.messages.test).to.not.be.undefined;
+    expect(round1.messages.alternate).to.be.undefined;
+
+    let state2 = getAlternateState();
+    state2.intl = fromJS(state2.intl);
+    const round2 = intlSelector(state2);
+    expect(round2.messages.test).to.not.be.undefined;
+    expect(round2.messages.alternate).to.be.undefined;
+  });
+
   function getState() {
     return {
       intl: {