diff --git a/matlab/set_prior.m b/matlab/set_prior.m
index c661c8620..e701b2c10 100644
--- a/matlab/set_prior.m
+++ b/matlab/set_prior.m
@@ -221,4 +221,38 @@ function [xparam1, estim_params_, bayestopt_, lb, ub, M_]=set_prior(estim_params
     end
     
     k = find(isnan(xparam1));
-    xparam1(k) = bayestopt_.p1(k);
\ No newline at end of file
+    xparam1(k) = bayestopt_.p1(k);
+
+    CheckPath('prior');
+
+    if exist([ M_.dname '/prior/definition.mat'])
+        bayestopt_old = load([M_.dname '/prior/definition.mat'],'bayestopt_');
+        prior_has_changed = 0;
+        if any(bayestopt_.p1-bayestopt_old.p1)
+            prior_has_changed = 1;
+        end
+        if any(bayestopt_.p2-bayestopt_old.p2)
+            prior_has_changed = 1;
+        end
+        if any(bayestopt_.p3-bayestopt_old.p3)
+            prior_has_changed = 1;
+        end
+        if any(bayestopt_.p4-bayestopt_old.p4)
+            prior_has_changed = 1;
+        end
+        if any(bayestopt_.p5-bayestopt_old.p5)
+            prior_has_changed = 1;
+        end
+        if any(bayestopt_.p6-bayestopt_old.p6)
+            prior_has_changed = 1;
+        end
+        if any(bayestopt_.p7-bayestopt_old.p7)
+            prior_has_changed = 1;
+        end
+        if prior_has_changed
+            delete([M_.dname '/prior/definition.mat']);
+            save([M_.dname '/prior/definition.mat'],'bayestopt_');
+        end
+    else
+        save([M_.dname '/prior/definition.mat'],'bayestopt_');
+    end
\ No newline at end of file