diff --git a/README.md b/README.md
index 4b04836f..1cdcc00d 100644
--- a/README.md
+++ b/README.md
@@ -51,6 +51,7 @@ Requirements for Building VeraCrypt for Windows:
   header files (available at ftp://ftp.rsasecurity.com/pub/pkcs/pkcs-11/v2-20)
 - NASM assembler 2.08 or compatible
 - gzip compressor
+- upx packer (available at http://upx.sourceforge.net/)
 
 IMPORTANT: