diff --git a/matlab/prior_sampler.m b/matlab/prior_sampler.m
index f3d97c79cdcc5d58bae325268e88866bd941ee2f..87ffe449f1cd83cbc09abd6177930c9137a1fa89 100644
--- a/matlab/prior_sampler.m
+++ b/matlab/prior_sampler.m
@@ -87,7 +87,7 @@ set(hh,'Name','Prior sampler.');
 
 % Simulations.
 while iteration < NumberOfSimulations
-    if ~mod(t,10)
+    if ~mod(iteration,10)
         dyn_waitbar(iteration/NumberOfSimulations,hh,'Please wait. Prior sampler...');
     end
     loop_indx = loop_indx+1;