diff --git a/migopy/__init__.py b/migopy/__init__.py
index e9b6081..d065329 100644
--- a/migopy/__init__.py
+++ b/migopy/__init__.py
@@ -236,9 +236,10 @@ def ignore(self, spec_migr=None):
     @task
     def rollback(self, spec_migr):
         """Rollback specyfic migration"""
-        if spec_migr not in self.unregistered():
-            raise MigopyException(('Migration %s is not on unregistred ' +
-                                   'migrations list. Can not be executed') %
+        if spec_migr in self.unregistered():
+            raise MigopyException(('Migration %s is on unregistred ' +
+                                   'migrations list. ' +
+                                   'Can not be executed rollback') %
                                   spec_migr)
         spec_migr_name = re.sub('\.py$', '', spec_migr)
         with cwd_in_syspath():