diff --git a/pymc/model.py b/pymc/model.py
index 7d3972a4c6a..490bd08b9fb 100644
--- a/pymc/model.py
+++ b/pymc/model.py
@@ -1456,7 +1456,7 @@ def make_obs_var(
 
             # Create deterministic that combines observed and missing
             # Note: This can widely increase memory consumption during sampling for large datasets
-            rv_var = at.zeros(data.shape)
+            rv_var = at.empty(data.shape, dtype=observed_rv_var.type.dtype)
             rv_var = at.set_subtensor(rv_var[mask.nonzero()], missing_rv_var)
             rv_var = at.set_subtensor(rv_var[antimask_idx], observed_rv_var)
             rv_var = Deterministic(name, rv_var, self, dims)
diff --git a/pymc/tests/test_model.py b/pymc/tests/test_model.py
index 84f814e6104..aea3f730258 100644
--- a/pymc/tests/test_model.py
+++ b/pymc/tests/test_model.py
@@ -356,6 +356,9 @@ def test_missing_data(self):
 
         assert m["x2_missing"].type == gf._extra_vars_shared["x2_missing"].type
 
+        # The dtype of the merged observed/missing deterministic should match the RV dtype
+        assert m.deterministics[0].type.dtype == x2.type.dtype
+
         pnt = m.initial_point(random_seed=None).copy()
         del pnt["x2_missing"]