diff --git a/pymc/distributions/transforms.py b/pymc/distributions/transforms.py
index 023ff57679..c4e0d6456f 100644
--- a/pymc/distributions/transforms.py
+++ b/pymc/distributions/transforms.py
@@ -333,8 +333,8 @@ def log_jac_det(self, value, *rv_inputs):
 def extend_axis(array, axis):
     n = array.shape[axis] + 1
     sum_vals = array.sum(axis, keepdims=True)
-    norm = sum_vals / (np.sqrt(n) + n)
-    fill_val = norm - sum_vals / np.sqrt(n)
+    norm = sum_vals / (at.sqrt(n) + n)
+    fill_val = norm - sum_vals / at.sqrt(n)
 
     out = at.concatenate([array, fill_val], axis=axis)
     return out - norm
@@ -346,8 +346,8 @@ def extend_axis_rev(array, axis):
     n = array.shape[normalized_axis]
     last = at.take(array, [-1], axis=normalized_axis)
 
-    sum_vals = -last * np.sqrt(n)
-    norm = sum_vals / (np.sqrt(n) + n)
+    sum_vals = -last * at.sqrt(n)
+    norm = sum_vals / (at.sqrt(n) + n)
     slice_before = (slice(None, None),) * normalized_axis
 
     return array[slice_before + (slice(None, -1),)] + norm