diff --git a/Viewer/Makefile b/Viewer/Makefile
index c5fc3e23..9c0fc7f4 100755
--- a/Viewer/Makefile
+++ b/Viewer/Makefile
@@ -38,7 +38,7 @@
 ## 	APP_NAME	- Application name
 ## 	APP_BIN		- App binary name (ignored for MacOS)
 ##
-## 	ARCH		- target achitecture (ia32, x86)
+## 	ARCH		- target achitecture (ia32, x86, x64, ...)
 ## 	TARGET_OS	- target OS (win32, linux, darwin)
 ##
 ## 	ELECTRON_DOWNOAD_URL
diff --git a/Viewer/doc/MAKE b/Viewer/doc/MAKE
index 6a890069..9f331c6c 100644
--- a/Viewer/doc/MAKE
+++ b/Viewer/doc/MAKE
@@ -9,7 +9,7 @@ Variables to control the build:
 	APP_NAME	- Application name
 	APP_BIN		- App binary name (ignored for MacOS)
 
-	ARCH		- target achitecture (ia32, x86)
+	ARCH		- target achitecture (ia32, x86, x64, ...)
 	TARGET_OS	- target OS (win32, linux, darwin)
 
 	ELECTRON_DOWNOAD_URL