diff --git a/lib/output.js b/lib/output.js
index e539bc1b..f5040050 100644
--- a/lib/output.js
+++ b/lib/output.js
@@ -1053,7 +1053,10 @@ function OutputStream(options) {
         output.print(self.operator);
     });
     DEFPRINT(AST_Binary, function(self, output){
+        var isYield = (self.left.operator == "yield" || self.left.operator === "yield*");
+        isYield && output.print("(");
         self.left.print(output);
+        isYield && output.print(")");
         output.space();
         output.print(self.operator);
         if (self.operator == "<"
@@ -1068,7 +1071,7 @@ function OutputStream(options) {
             // the space is optional depending on "beautify"
             output.space();
         }
-        var isYield = (self.right.operator == "yield" || self.right.operator === "yield*");
+        isYield = (self.right.operator == "yield" || self.right.operator === "yield*");
         isYield && output.print("(");
         self.right.print(output);
         isYield && output.print(")");