diff --git a/programs/pkey/mpi_demo.c b/programs/pkey/mpi_demo.c
index c94fb97..95267fc 100644
--- a/programs/pkey/mpi_demo.c
+++ b/programs/pkey/mpi_demo.c
@@ -96,7 +96,7 @@
 
     if( ret != 0 )
     {
-        polarssl_printf( "\nAn error occured.\n" );
+        polarssl_printf( "\nAn error occurred.\n" );
         ret = 1;
     }