diff --git a/src/d_iwad.cpp b/src/d_iwad.cpp
index 0999a77ea..705ff2f72 100644
--- a/src/d_iwad.cpp
+++ b/src/d_iwad.cpp
@@ -269,6 +269,10 @@ void FIWadManager::ParseIWadInfos(const char *fn)
 		}
 		delete resfile;
 	}
+	if (mIWadNames.Size() == 0 || mIWads.Size() == 0)
+	{
+		I_FatalError("No IWAD definitions found");
+	}
 }