diff --git a/src/Moq/ReturnsExtensions.cs b/src/Moq/ReturnsExtensions.cs
index ee96fcaf4..14df738ef 100644
--- a/src/Moq/ReturnsExtensions.cs
+++ b/src/Moq/ReturnsExtensions.cs
@@ -339,7 +339,7 @@ static TimeSpan GetDelay(TimeSpan minDelay, TimeSpan maxDelay, Random random)
 
         static TimeSpan GetDelay(TimeSpan minDelay, TimeSpan maxDelay, Random random)
         {
-            if (!(minDelay < maxDelay))
+            if (minDelay >= maxDelay)
                 throw new ArgumentException(Resources.MinDelayMustBeLessThanMaxDelay);
 
             var min = (int)minDelay.Ticks;