diff --git a/GPy/inference/latent_function_inference/var_gauss.py b/GPy/inference/latent_function_inference/var_gauss.py
index e71416b4..bef1cce6 100644
--- a/GPy/inference/latent_function_inference/var_gauss.py
+++ b/GPy/inference/latent_function_inference/var_gauss.py
@@ -47,7 +47,10 @@ class VarGauss(LatentFunctionInference):
             dL_dthetaL = np.array([])
         dF_da = np.dot(K, dF_dm)
         SigmaB = Sigma*self.beta
-        dF_db = -np.diag(Sigma.dot(np.diag(dF_dv.flatten())).dot(SigmaB))*2
+        #dF_db_ = -np.diag(Sigma.dot(np.diag(dF_dv.flatten())).dot(SigmaB))*2
+        dF_db = -2*np.sum(Sigma**2 * (dF_dv * self.beta), 0)
+        #assert np.allclose(dF_db, dF_db_)
+
         KL = 0.5*(Alogdet + np.trace(Ai) - num_data + np.sum(m*self.alpha))
         dKL_da = m
         A_A2 = Ai - Ai.dot(Ai)