diff --git a/Library/Homebrew/cmd/update.sh b/Library/Homebrew/cmd/update.sh
index a7c384a5af..19ece3f2d0 100644
--- a/Library/Homebrew/cmd/update.sh
+++ b/Library/Homebrew/cmd/update.sh
@@ -599,7 +599,6 @@ EOS
         -d "$HOMEBREW_LIBRARY/LinkedKegs" ||
         (-n "$HOMEBREW_DEVELOPER" && -z "$HOMEBREW_UPDATE_PREINSTALL") ]]
   then
-    unset HOMEBREW_RUBY_PATH
     brew update-report "$@"
     return $?
   elif [[ -z "$HOMEBREW_UPDATE_PREINSTALL" ]]