diff --git a/samples/c/delaunay.c b/samples/c/delaunay.c
index 896d70d0d4..bad0b0afae 100644
--- a/samples/c/delaunay.c
+++ b/samples/c/delaunay.c
@@ -1,4 +1,5 @@
 #include <opencv2/imgproc/imgproc_c.h>
+#include <opencv2/legacy/legacy.hpp>
 #include "opencv2/highgui/highgui.hpp"
 
 #include <stdio.h>