diff --git a/Octokit/Models/Request/LabelUpdate.cs b/Octokit/Models/Request/LabelUpdate.cs
index fa8b76ea..9486aedb 100644
--- a/Octokit/Models/Request/LabelUpdate.cs
+++ b/Octokit/Models/Request/LabelUpdate.cs
@@ -1,7 +1,12 @@
-namespace Octokit
+using System;
+using System.Text.RegularExpressions;
+
+namespace Octokit
 {
     public class LabelUpdate
     {
+        private string _color;
+
         public LabelUpdate(string name, string color)
         {
             Name = name;
@@ -16,6 +21,20 @@
         /// <summary>
         /// Color of the label (required).
         /// </summary>
-        public string Color { get; set; }
+        public string Color
+        {
+            get { return _color; }
+            set
+            {
+                if (string.IsNullOrEmpty(value)
+                    || value.Length != 6
+                    || !Regex.IsMatch(value, @"\A\b[0-9a-fA-F]+\b\Z"))
+                {
+                    throw new ArgumentOutOfRangeException("value", "Color should be an hexadecimal string of length 6");
+                }
+
+                _color = value;
+            }
+        }
     }
 }
diff --git a/Octokit/Models/Request/NewLabel.cs b/Octokit/Models/Request/NewLabel.cs
index 8b123f12..5f37f8b7 100644
--- a/Octokit/Models/Request/NewLabel.cs
+++ b/Octokit/Models/Request/NewLabel.cs
@@ -29,9 +29,9 @@ namespace Octokit
             get { return _color; }
             set
             {
-                if (!string.IsNullOrEmpty(value)
-                    && value.Length == 6
-                    && Regex.IsMatch(value, @"\A\b[0-9a-fA-F]+\b\Z"))
+                if (string.IsNullOrEmpty(value)
+                    || value.Length != 6
+                    || !Regex.IsMatch(value, @"\A\b[0-9a-fA-F]+\b\Z"))
                 {
                     throw new ArgumentOutOfRangeException("value", "Color should be an hexadecimal string of length 6");
                 }