diff --git a/Source/Core/Windows/MainForm.cs b/Source/Core/Windows/MainForm.cs
index 7410c9559d104779e3597d0d69e466e5b0029f3e..d9f04220771f30ff55aa59c524a2a70a66787bcc 100755
--- a/Source/Core/Windows/MainForm.cs
+++ b/Source/Core/Windows/MainForm.cs
@@ -440,6 +440,8 @@ namespace CodeImp.DoomBuilder.Windows
 		private void UpdateTitle()
 		{
             string programname = this.Text = Application.ProductName + " R" + General.ThisAssembly.GetName().Version.Revision;
+            if (Environment.Is64BitProcess)
+                programname += " (64-bit)";
 
             // Map opened?
             if (General.Map != null)