diff --git a/examples/osgdrawinstanced/osgdrawinstanced.cpp b/examples/osgdrawinstanced/osgdrawinstanced.cpp
index 87d856e7d..f07e0dfac 100644
--- a/examples/osgdrawinstanced/osgdrawinstanced.cpp
+++ b/examples/osgdrawinstanced/osgdrawinstanced.cpp
@@ -59,6 +59,8 @@ createStateSet()
     // render each instance uniquely. gl_InstanceID will be in the range
     // 0 to numInstances-1 (1023 in our case).
     std::string vertexSource =
+        "#version 120\n"
+        "#extension GL_ARB_draw_instanced : enable\n"
         "uniform sampler2D osgLogo; \n"
         "uniform float osg_SimulationTime; \n"