diff --git a/docs/source/api/apollo-server.md b/docs/source/api/apollo-server.md
index 36fdc322e0c..26de3c21e7f 100644
--- a/docs/source/api/apollo-server.md
+++ b/docs/source/api/apollo-server.md
@@ -51,6 +51,21 @@ new ApolloServer({
 		authScope: getScope(req.headers.authorization)
 	}),
 });
+```
+
+  * `rootValue`: <`Any`> | <`Function`>
+
+    A value or function called with the parsed `Document`, creating the root value passed to the graphql executor. The function is useful if you wish to provide a different root value based on the query operation type.
+
+```js
+new ApolloServer({
+  typeDefs,
+  resolvers,
+  rootValue: (documentAST) => ({
+    const op = getOperationAST(documentNode)
+    return op === 'mutation' ? mutationRoot : queryRoot;
+  })
+});
 ```
 
 * `mocks`: <`Object`> | <`Boolean`>