diff --git a/Octokit/Models/Response/Author.cs b/Octokit/Models/Response/Author.cs
index e203f51a..8667f76e 100644
--- a/Octokit/Models/Response/Author.cs
+++ b/Octokit/Models/Response/Author.cs
@@ -15,8 +15,9 @@ namespace Octokit
         public string AvatarUrl { get; set; }
 
         /// <summary>
-        /// Hex Gravatar identifier
+        /// Hex Gravatar identifier, now obsolete
         /// </summary>
+        [Obsolete("This property is now obsolete, use AvatarUrl instead")]
         public string GravatarId { get; set; }
 
         public string Url { get; set; }
diff --git a/Octokit/Models/Response/User.cs b/Octokit/Models/Response/User.cs
index 5e55bf35..eb04d475 100644
--- a/Octokit/Models/Response/User.cs
+++ b/Octokit/Models/Response/User.cs
@@ -11,8 +11,9 @@ namespace Octokit
     public class User : Account
     {
         /// <summary>
-        /// Hex Gravatar identifier
+        /// Hex Gravatar identifier, now obsolete
         /// </summary>
+        [Obsolete("This property is now obsolete, use AvatarUrl instead")]
         public string GravatarId { get; set; }
 
         /// <summary>