diff --git a/samples/python/houghlines.py b/samples/python/houghlines.py
index 120d8bbaae..98c3640147 100755
--- a/samples/python/houghlines.py
+++ b/samples/python/houghlines.py
@@ -36,16 +36,17 @@ if __name__ == '__main__':
 
     else:    # HoughLines
         lines = cv2.HoughLines(dst, 1, math.pi/180.0, 50, np.array([]), 0, 0)
-        a,b,c = lines.shape
-        for i in range(a):
-            rho = lines[i][0][0]
-            theta = lines[i][0][1]
-            a = math.cos(theta)
-            b = math.sin(theta)
-            x0, y0 = a*rho, b*rho
-            pt1 = ( int(x0+1000*(-b)), int(y0+1000*(a)) )
-            pt2 = ( int(x0-1000*(-b)), int(y0-1000*(a)) )
-            cv2.line(cdst, pt1, pt2, (0, 0, 255), 3, cv2.LINE_AA)
+        if lines != None:
+            a,b,c = lines.shape
+            for i in range(a):
+                rho = lines[i][0][0]
+                theta = lines[i][0][1]
+                a = math.cos(theta)
+                b = math.sin(theta)
+                x0, y0 = a*rho, b*rho
+                pt1 = ( int(x0+1000*(-b)), int(y0+1000*(a)) )
+                pt2 = ( int(x0-1000*(-b)), int(y0-1000*(a)) )
+                cv2.line(cdst, pt1, pt2, (0, 0, 255), 3, cv2.LINE_AA)
 
     cv2.imshow("source", src)
     cv2.imshow("detected lines", cdst)