diff --git a/examples_ptx/ptxgen/Makefile b/examples_ptx/ptxgen/Makefile
index 3e47d89e..388886fa 100644
--- a/examples_ptx/ptxgen/Makefile
+++ b/examples_ptx/ptxgen/Makefile
@@ -1,7 +1,7 @@
 CUDA55 = /usr/local/cuda-5.5
 CUDA60 = /usr/local/cuda-6.0
-CUDA55 = /opt/cuda/5.5
-CUDA60 = /opt/cuda/5.5
+#CUDA55 = /opt/cuda/5.5
+#CUDA60 = /opt/cuda/5.5
 all: ptxgen55 ptxgen60
 
 ptxgen60: ptxgen.cpp