diff --git a/src/coff/pe.h b/src/coff/pe.h
index 601a68e..3a43174 100644
--- a/src/coff/pe.h
+++ b/src/coff/pe.h
@@ -151,7 +151,6 @@
 #define IMAGE_FILE_MACHINE_THUMB             0x01c2
 #define IMAGE_FILE_MACHINE_TRICORE           0x0520
 #define IMAGE_FILE_MACHINE_WCEMIPSV2         0x0169
-#define IMAGE_FILE_MACHINE_AMD64             0x8664
 
 #define IMAGE_SUBSYSTEM_UNKNOWN			 0
 #define IMAGE_SUBSYSTEM_NATIVE			 1