diff --git a/stargan/attacks.py b/stargan/attacks.py
index 49a29ee..cbf3f79 100644
--- a/stargan/attacks.py
+++ b/stargan/attacks.py
@@ -35,7 +35,7 @@ class LinfPGDAttack(object):
                 y = torch.FloatTensor(y).to(self.device)
 
             self.model.zero_grad()
-            loss = -self.loss_fn(output, y)
+            loss = self.loss_fn(output, y)
             loss.backward()
             grad = X.grad