diff --git a/src/createStore.js b/src/createStore.js
index bfe9d69123..36aaf21e36 100644
--- a/src/createStore.js
+++ b/src/createStore.js
@@ -196,6 +196,17 @@ export default function createStore(reducer, preloadedState, enhancer) {
       throw new Error('Expected the nextReducer to be a function.')
     }
 
+    const reducerShape = nextReducer({}, {})
+
+    if (typeof currentState === 'object' && Array.isArray(currentState) === false) {
+      currentState = Object.keys(currentState).reduce((targetShape, key) => {
+        if (key in reducerShape) {
+          targetShape[key] = currentState[key]
+        }
+        return targetShape
+      }, {})
+    }
+
     currentReducer = nextReducer
     dispatch({ type: ActionTypes.INIT })
   }
diff --git a/test/createStore.spec.js b/test/createStore.spec.js
index 90e60b73b2..a4e25b9ccd 100644
--- a/test/createStore.spec.js
+++ b/test/createStore.spec.js
@@ -601,6 +601,21 @@ describe('createStore', () => {
     ).not.toThrow()
   })
 
+  it('does not warn if replaceReducer changes reducer shape', () => {
+    const preSpy = console.error
+    const spy = jest.fn()
+    console.error = spy
+
+    const store = createStore(combineReducers({ foo: reducers.todos }))
+    expect(spy.mock.calls.length).toBe(0)
+
+    store.replaceReducer(combineReducers({ bar: reducers.todos }))
+    expect(spy.mock.calls.length).toBe(0)
+
+    spy.mockClear()
+    console.error = preSpy    
+  })
+
   it('throws if listener is not a function', () => {
     const store = createStore(reducers.todos)