diff --git a/spring-test/src/test/java/org/springframework/test/web/reactive/server/HttpHandlerConnectorTests.java b/spring-test/src/test/java/org/springframework/test/web/reactive/server/HttpHandlerConnectorTests.java
index d84214d8aa..fff798caf0 100644
--- a/spring-test/src/test/java/org/springframework/test/web/reactive/server/HttpHandlerConnectorTests.java
+++ b/spring-test/src/test/java/org/springframework/test/web/reactive/server/HttpHandlerConnectorTests.java
@@ -84,7 +84,7 @@ public class HttpHandlerConnectorTests {
 		TestHttpHandler handler = new TestHttpHandler(response -> {
 			response.setStatusCode(HttpStatus.OK);
 			response.getHeaders().put("custom-header", Arrays.asList("h0", "h1"));
-			response.getCookies().add(cookie.getName(), cookie);
+			response.addCookie(cookie);
 			return response.writeWith(Mono.just(toDataBuffer("Custom body")));
 		});
 
diff --git a/spring-web/src/main/java/org/springframework/http/server/reactive/AbstractServerHttpResponse.java b/spring-web/src/main/java/org/springframework/http/server/reactive/AbstractServerHttpResponse.java
index 3ede8a5627..20fa7a0ce9 100644
--- a/spring-web/src/main/java/org/springframework/http/server/reactive/AbstractServerHttpResponse.java
+++ b/spring-web/src/main/java/org/springframework/http/server/reactive/AbstractServerHttpResponse.java
@@ -120,6 +120,19 @@ public abstract class AbstractServerHttpResponse implements ServerHttpResponse {
 				CollectionUtils.unmodifiableMultiValueMap(this.cookies) : this.cookies);
 	}
 
+	@Override
+	public void addCookie(ResponseCookie cookie) {
+		Assert.notNull(cookie, "'cookie' must not be null");
+
+		if (this.state.get() == State.COMMITTED) {
+			throw new IllegalStateException("Can't add the cookie " + cookie +
+					"because the HTTP response has already been committed");
+		}
+		else {
+			getCookies().add(cookie.getName(), cookie);
+		}
+	}
+
 	@Override
 	public String encodeUrl(String url) {
 		return (this.urlEncoder != null ? this.urlEncoder.apply(url) : url);
diff --git a/spring-web/src/main/java/org/springframework/http/server/reactive/ServerHttpResponse.java b/spring-web/src/main/java/org/springframework/http/server/reactive/ServerHttpResponse.java
index 63c55ea4fd..e2b0b7a5dc 100644
--- a/spring-web/src/main/java/org/springframework/http/server/reactive/ServerHttpResponse.java
+++ b/spring-web/src/main/java/org/springframework/http/server/reactive/ServerHttpResponse.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -50,6 +50,13 @@ public interface ServerHttpResponse extends ReactiveHttpOutputMessage {
 	 */
 	MultiValueMap<String, ResponseCookie> getCookies();
 
+	/**
+	 * Add the given {@code ResponseCookie}.
+	 * @param cookie the cookie to add
+	 * @throws IllegalStateException if the response has already been committed
+	 */
+	void addCookie(ResponseCookie cookie);
+
 	/**
 	 * A mechanism for URL rewriting that applications and libraries such as
 	 * HTML template libraries to use consistently for all URLs emitted by
diff --git a/spring-web/src/main/java/org/springframework/http/server/reactive/ServerHttpResponseDecorator.java b/spring-web/src/main/java/org/springframework/http/server/reactive/ServerHttpResponseDecorator.java
index 4d99573d22..06328b5235 100644
--- a/spring-web/src/main/java/org/springframework/http/server/reactive/ServerHttpResponseDecorator.java
+++ b/spring-web/src/main/java/org/springframework/http/server/reactive/ServerHttpResponseDecorator.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -74,6 +74,11 @@ public class ServerHttpResponseDecorator implements ServerHttpResponse {
 		return getDelegate().getCookies();
 	}
 
+	@Override
+	public void addCookie(ResponseCookie cookie) {
+		getDelegate().addCookie(cookie);
+	}
+
 	@Override
 	public String encodeUrl(String url) {
 		return getDelegate().encodeUrl(url);