diff --git a/src/NzbDrone.Core/Download/Clients/Transmission/TransmissionSettings.cs b/src/NzbDrone.Core/Download/Clients/Transmission/TransmissionSettings.cs
index 0e18f6e26..51504f054 100644
--- a/src/NzbDrone.Core/Download/Clients/Transmission/TransmissionSettings.cs
+++ b/src/NzbDrone.Core/Download/Clients/Transmission/TransmissionSettings.cs
@@ -1,4 +1,4 @@
-using System;
+using System.Text.RegularExpressions;
 using FluentValidation;
 using NzbDrone.Core.Annotations;
 using NzbDrone.Core.ThingiProvider;
@@ -15,7 +15,7 @@ public TransmissionSettingsValidator()
 
             RuleFor(c => c.UrlBase).ValidUrlBase();
 
-            RuleFor(c => c.TvCategory).Matches(@"^\.?[-a-z]*$").WithMessage("Allowed characters a-z and -");
+            RuleFor(c => c.TvCategory).Matches(@"^\.?[-a-z]*$", RegexOptions.IgnoreCase).WithMessage("Allowed characters a-z and -");
         }
     }