diff --git a/interfaces/cython/cantera/test/test_thermo.py b/interfaces/cython/cantera/test/test_thermo.py
index d0d12a392..023df57b7 100644
--- a/interfaces/cython/cantera/test/test_thermo.py
+++ b/interfaces/cython/cantera/test/test_thermo.py
@@ -682,6 +682,9 @@ class TestSpecies(utilities.CanteraTest):
         self.assertEqual(s.size, 1.0)
         self.assertEqual(s.charge, 0.0)
 
+        self.assertIsNone(s.thermo)
+        self.assertIsNone(s.transport)
+
     def test_index_accessor(self):
         for k in range(self.gas.n_species):
             s = self.gas.species(k)
diff --git a/interfaces/cython/cantera/thermo.pyx b/interfaces/cython/cantera/thermo.pyx
index 5bd0363b8..7497ddba7 100644
--- a/interfaces/cython/cantera/thermo.pyx
+++ b/interfaces/cython/cantera/thermo.pyx
@@ -153,7 +153,10 @@ cdef class Species:
         of class `SpeciesThermo`.
         """
         def __get__(self):
-            return wrapSpeciesThermo(self.species.thermo)
+            if self.species.thermo.get() != NULL:
+                return wrapSpeciesThermo(self.species.thermo)
+            else:
+                return None
 
         def __set__(self, SpeciesThermo spthermo):
             self.species.thermo = spthermo._spthermo
@@ -164,9 +167,12 @@ cdef class Species:
         `GasTransportData`.
         """
         def __get__(self):
-            data = GasTransportData(init=False)
-            data._assign(self.species.transport)
-            return data
+            if self.species.transport.get() != NULL:
+                data = GasTransportData(init=False)
+                data._assign(self.species.transport)
+                return data
+            else:
+                return None
         def __set__(self, GasTransportData tran):
             self.species.transport = tran._data