diff --git a/CHANGELOG.md b/CHANGELOG.md
index 57661775b..b44b11603 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,12 +1,13 @@
 # Changelog
 
 ### vNEXT
+- Add Validation step to server [PR #241](https://github.com/apollographql/subscriptions-transport-ws/pull/241)
+- Call operation handler before delete the operation on operation complete [PR #239](https://github.com/apollographql/subscriptions-transport-ws/pull/239)
 
 ### 0.8.1
 - Send first keep alive message right after the ack [PR #223](https://github.com/apollographql/subscriptions-transport-ws/pull/223)
 - Return after first post-install when it should install dev dependencies [PR #218](https://github.com/apollographql/subscriptions-transport-ws/pull/218)
 - On installing from branch install dev dependencies only if dist folder isnt found [PR #219](https://github.com/apollographql/subscriptions-transport-ws/pull/219)
-- Call operation handler before delete the operation on operation complete [PR #239](https://github.com/apollographql/subscriptions-transport-ws/pull/239)
 
 ### 0.8.0
 - Expose opId `onOperationComplete` method [PR #211](https://github.com/apollographql/subscriptions-transport-ws/pull/211)
diff --git a/src/server.ts b/src/server.ts
index 10aead6a1..f15e7ca6f 100644
--- a/src/server.ts
+++ b/src/server.ts
@@ -4,7 +4,15 @@ import MessageTypes from './message-types';
 import { GRAPHQL_WS, GRAPHQL_SUBSCRIPTIONS } from './protocol';
 import { SubscriptionManager } from 'graphql-subscriptions';
 import isObject = require('lodash.isobject');
-import { parse, ExecutionResult, GraphQLSchema, DocumentNode } from 'graphql';
+import {
+  parse,
+  ExecutionResult,
+  GraphQLSchema,
+  DocumentNode,
+  validate,
+  ValidationContext,
+  specifiedRules,
+} from 'graphql';
 import { executeFromSubscriptionManager } from './adapters/subscription-manager';
 import { createEmptyIterable } from './utils/empty-iterable';
 import { createAsyncIterator, forAwaitEach, isAsyncIterable } from 'iterall';
@@ -57,6 +65,7 @@ export interface ServerOptions {
   schema?: GraphQLSchema;
   execute?: ExecuteFunction;
   subscribe?: SubscribeFunction;
+  validationRules?: Array<(context: ValidationContext) => any>;
 
   onOperation?: Function;
   onOperationComplete?: Function;
@@ -90,6 +99,7 @@ export class SubscriptionServer {
   private schema: GraphQLSchema;
   private rootValue: any;
   private keepAlive: number;
+  private specifiedRules: Array<(context: ValidationContext) => any>;
 
   /**
    * @deprecated onSubscribe is deprecated, use onOperation instead
@@ -110,6 +120,7 @@ export class SubscriptionServer {
       onOperationComplete, onConnect, onDisconnect, keepAlive,
     } = options;
 
+    this.specifiedRules = options.validationRules || specifiedRules;
     this.loadExecutor(options);
 
     this.onOperation = onSubscribe ? onSubscribe : onOperation;
@@ -360,8 +371,20 @@ export class SubscriptionServer {
 
               const document = typeof baseParams.query !== 'string' ? baseParams.query : parse(baseParams.query);
               let executionIterable: AsyncIterator<ExecutionResult>;
+              let validationErrors: Error[] = [];
 
-              if (this.subscribe && isASubscriptionOperation(document, params.operationName)) {
+              if ( this.schema ) {
+                // NOTE: This is a temporary condition to support the legacy subscription manager.
+                // As soon as subscriptionManager support is removed, we can remove the if
+                // and keep only the validation part.
+                validationErrors = validate(this.schema, document, this.specifiedRules);
+              }
+
+              if ( validationErrors.length > 0 ) {
+                executionIterable = createIterableFromPromise<ExecutionResult>(
+                  Promise.resolve({ errors: validationErrors }),
+                );
+              } else if (this.subscribe && isASubscriptionOperation(document, params.operationName)) {
                 executionIterable = this.subscribe(this.schema,
                   document,
                   this.rootValue,
diff --git a/src/test/tests.ts b/src/test/tests.ts
index c1fd2a86d..d9a24c847 100644
--- a/src/test/tests.ts
+++ b/src/test/tests.ts
@@ -14,7 +14,7 @@ import {
 } from 'chai';
 import * as sinon from 'sinon';
 import * as WebSocket from 'ws';
-import { execute, subscribe } from 'graphql';
+import { specifiedRules, execute, subscribe } from 'graphql';
 
 Object.assign(global, {
   WebSocket: WebSocket,
@@ -2033,6 +2033,48 @@ describe('Client<->Server Flow', () => {
     });
   });
 
+  it('validate requests against schema', (done) => {
+    const testServer = createServer(notFoundRequestListener);
+    testServer.listen(SERVER_EXECUTOR_TESTS_PORT);
+
+    SubscriptionServer.create({
+      schema: subscriptionsSchema,
+      execute,
+      subscribe,
+      validationRules: specifiedRules,
+    }, {
+      server: testServer,
+      path: '/',
+    });
+
+    const client = new SubscriptionClient(`ws://localhost:${SERVER_EXECUTOR_TESTS_PORT}/`);
+    let isFirstTime = true;
+
+    client.onConnected(async () => {
+      // Manually close the connection only in the first time, to avoid infinite loop
+      if (isFirstTime) {
+        isFirstTime = false;
+
+        setTimeout(() => {
+          // Disconnect the client
+          client.close(false);
+
+          // Subscribe to data, without manually reconnect before
+          const opId = client.subscribe({
+            query: `query { invalid }`,
+            variables: {},
+          }, (err, res) => {
+            expect(opId).not.to.eq(null);
+            expect(res).to.eq(null);
+            expect(err[0].message).to.eq('Cannot query field "invalid" on type "Query".');
+            testServer.close();
+            done();
+          });
+        }, 300);
+      }
+    });
+  });
+
   it('should close iteration over AsyncIterator when client unsubscribes', async () => {
     subscriptionAsyncIteratorSpy.reset();
     resolveAsyncIteratorSpy.reset();