diff --git a/src/build/feature.jam b/src/build/feature.jam
index 41d6caf53..4b980ab21 100644
--- a/src/build/feature.jam
+++ b/src/build/feature.jam
@@ -118,7 +118,15 @@ rule feature (
     {
         error = free features cannot be propagated ;
     }
-
+    else 
+    {
+        local m = [ MATCH (.*=.*) : $(values) ] ;
+        if $(m[1])
+        {
+            error = "feature value may not contain '='" ;
+        }        
+    }
+    
     if $(error)
     {
         errors.error $(error)