diff --git a/src/JsonMapper.php b/src/JsonMapper.php
index 6e5ebac09..5102d9c1a 100644
--- a/src/JsonMapper.php
+++ b/src/JsonMapper.php
@@ -307,7 +307,7 @@ protected function inspectProperty(ReflectionClass $rc, $name)
         }
 
         // Parameter could not be directly set, so lets go for setter methods
-        $setter = 'set' . ucfirst($name);
+        $setter = 'set' . str_replace(' ', '', ucwords(str_replace('_', ' ', $name)));
 
         if (!$rc->hasMethod($setter)) {
             if ($rc->hasProperty($name)) {