diff --git a/utils/utils.py b/utils/utils.py
index a27cad38..59fe1a8c 100755
--- a/utils/utils.py
+++ b/utils/utils.py
@@ -53,7 +53,10 @@ def labels_to_class_weights(labels, nc=80):
     # Get class weights (inverse frequency) from training labels
     labels = np.concatenate(labels, 0)  # labels.shape = (866643, 5) for COCO
     classes = labels[:, 0].astype(np.int)
-    weights = 1 / (np.bincount(classes, minlength=nc) + 1e-6)  # number of targets per class
+    n = np.bincount(classes, minlength=nc)
+    weights = np.zeros(nc)
+    i = n.nonzero()
+    weights[i] = 1 / n[i]  # number of targets per class
     weights /= weights.sum()
     return torch.Tensor(weights)