diff --git a/Source/OpenTK/Graphics/DisplayResolution.cs b/Source/OpenTK/Graphics/DisplayResolution.cs
index 1cf62357..b2f2d32a 100644
--- a/Source/OpenTK/Graphics/DisplayResolution.cs
+++ b/Source/OpenTK/Graphics/DisplayResolution.cs
@@ -24,10 +24,11 @@ namespace OpenTK.Graphics
 
         internal DisplayResolution(int width, int height, int bitsPerPixel, float refreshRate)
         {
+            // Refresh rate may be zero, since this information may not be available on some platforms.
             if (width <= 0) throw new ArgumentOutOfRangeException("width", "Must be greater than zero.");
             if (height <= 0) throw new ArgumentOutOfRangeException("height", "Must be greater than zero.");
             if (bitsPerPixel <= 0) throw new ArgumentOutOfRangeException("bitsPerPixel", "Must be greater than zero.");
-            if (refreshRate <= 0) throw new ArgumentOutOfRangeException("refreshRate", "Must be greater than zero.");
+            if (refreshRate < 0) throw new ArgumentOutOfRangeException("refreshRate", "Must be greater than zero.");
 
             this.width = width;
             this.height = height;