diff --git a/pomegranate/gmm.py b/pomegranate/gmm.py
index 65d7b483..38608994 100644
--- a/pomegranate/gmm.py
+++ b/pomegranate/gmm.py
@@ -156,11 +156,13 @@ def _initialize(self, X, sample_weight=None):
 		self.priors = _cast_as_parameter(torch.empty(self.k, 
 			dtype=self.dtype, device=self.device))
 
+		sample_weight_sum = sample_weight.sum()
 		for i in range(self.k):
 			idx = y_hat == i
 
-			self.distributions[i].fit(X[idx], sample_weight=sample_weight[idx])
-			self.priors[i] = idx.type(torch.float32).mean()
+			sample_weight_idx = sample_weight[idx]
+			self.distributions[i].fit(X[idx], sample_weight=sample_weight_idx)
+			self.priors[i] = sample_weight_idx.sum() / sample_weight_sum
 
 		self._initialized = True
 		self._reset_cache()