diff --git a/httpclient/src/main/java/org/apache/http/impl/cookie/BasicClientCookie.java b/httpclient/src/main/java/org/apache/http/impl/cookie/BasicClientCookie.java
index 8cfbf1f89..775b270c8 100644
--- a/httpclient/src/main/java/org/apache/http/impl/cookie/BasicClientCookie.java
+++ b/httpclient/src/main/java/org/apache/http/impl/cookie/BasicClientCookie.java
@@ -36,6 +36,8 @@ import java.util.HashMap;
 import java.util.Locale;
 import java.util.Map;
 
+import net.jcip.annotations.NotThreadSafe;
+
 import org.apache.http.cookie.ClientCookie;
 import org.apache.http.cookie.SetCookie;
 
@@ -49,6 +51,7 @@ import org.apache.http.cookie.SetCookie;
  *
  * @since 4.0
  */
+@NotThreadSafe
 public class BasicClientCookie implements SetCookie, ClientCookie, Cloneable {
 
     /**
diff --git a/httpclient/src/main/java/org/apache/http/impl/cookie/BasicClientCookie2.java b/httpclient/src/main/java/org/apache/http/impl/cookie/BasicClientCookie2.java
index 4b6235c5e..6385c1617 100644
--- a/httpclient/src/main/java/org/apache/http/impl/cookie/BasicClientCookie2.java
+++ b/httpclient/src/main/java/org/apache/http/impl/cookie/BasicClientCookie2.java
@@ -33,6 +33,8 @@ package org.apache.http.impl.cookie;
 
 import java.util.Date;
 
+import net.jcip.annotations.NotThreadSafe;
+
 import org.apache.http.cookie.SetCookie2;
 
 /**
@@ -43,6 +45,7 @@ import org.apache.http.cookie.SetCookie2;
  *
  * @since 4.0
  */
+@NotThreadSafe
 public class BasicClientCookie2 extends BasicClientCookie implements SetCookie2 {
 
     private String commentURL;