diff --git a/CMakeLists.txt b/CMakeLists.txt
index a442b9ea5..c6f9fd6ad 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -30,7 +30,7 @@ function( add_pk3 PK3_NAME PK3_DIR )
 			DEPENDS zipdir ${PK3_DIR} )
 	else( NOT NO_GENERATOR_EXPRESSIONS AND NOT ZDOOM_OUTPUT_OLDSTYLE )
 		add_custom_command( OUTPUT ${ZDOOM_OUTPUT_DIR}/${PK3_NAME}
-			COMMAND ${ZIPDIR_EXE} -udf ${ZDOOM_OUTPUT_DIR}/${PK3_NAME} ${PK3_DIR}/${PK3_NAME}
+			COMMAND ${ZIPDIR_EXE} -udf ${ZDOOM_OUTPUT_DIR}/${PK3_NAME} ${PK3_DIR}
 			DEPENDS zipdir ${PK3_DIR} )
 	endif( NOT NO_GENERATOR_EXPRESSIONS AND NOT ZDOOM_OUTPUT_OLDSTYLE )