diff --git a/interfaces/matlab/toolbox/@ThermoPhase/setState_SP.m b/interfaces/matlab/toolbox/@ThermoPhase/setState_SP.m
index 2b14d7696..ed9d99f26 100644
--- a/interfaces/matlab/toolbox/@ThermoPhase/setState_SP.m
+++ b/interfaces/matlab/toolbox/@ThermoPhase/setState_SP.m
@@ -7,9 +7,9 @@ function a = setState_SP(a,sp)
 %    entropy (J/kg/K) and pressure (Pa).
 %
 if sp(1) <= 0.0
-    error('the pressure must be positive');
-end
-if sp(2) <= 0.0
     error('the specific entropy must be positive');
 end
+if sp(2) <= 0.0
+    error('the pressure must be positive');
+end
 thermo_set(a.tp_id,23,sp);