diff --git a/src/glx/x11/glx_pbuffer.c b/src/glx/x11/glx_pbuffer.c
index 88a17df6f8d..01569213f2d 100644
--- a/src/glx/x11/glx_pbuffer.c
+++ b/src/glx/x11/glx_pbuffer.c
@@ -40,6 +40,23 @@
 #include "glcontextmodes.h"
 
 
+/**
+ * Emit a warning when clients use GLX 1.3 functions on pre-1.3 systems.
+ */
+static void
+warn_GLX_1_3(Display *dpy, const char *function_name)
+{
+   __GLXdisplayPrivate *priv = __glXInitialize(dpy);
+
+   if (priv->minorVersion < 3) {
+      fprintf(stderr, 
+	      "WARNING: Application calling GLX 1.3 function \"%s\" "
+	      "when GLX 1.3 is not supported!  This is an application bug!\n",
+	      function_name);
+   }
+}
+
+
 /**
  * Change a drawable's attribute.
  *
@@ -559,6 +576,8 @@ glXCreatePbuffer(Display * dpy, GLXFBConfig config, const int *attrib_list)
    width = 0;
    height = 0;
 
+   warn_GLX_1_3(dpy, __func__);
+
    for (i = 0; attrib_list[i * 2]; i++) {
       switch (attrib_list[i * 2]) {
       case GLX_PBUFFER_WIDTH:
@@ -592,6 +611,7 @@ PUBLIC void
 glXQueryDrawable(Display * dpy, GLXDrawable drawable,
                  int attribute, unsigned int *value)
 {
+   warn_GLX_1_3(dpy, __func__);
    GetDrawableAttribute(dpy, drawable, attribute, value);
 }
 
@@ -645,6 +665,8 @@ PUBLIC GLXPixmap
 glXCreatePixmap(Display * dpy, GLXFBConfig config, Pixmap pixmap,
                 const int *attrib_list)
 {
+   warn_GLX_1_3(dpy, __func__);
+
    return CreateDrawable(dpy, (__GLcontextModes *) config,
                          (Drawable) pixmap, attrib_list, X_GLXCreatePixmap);
 }
@@ -654,6 +676,8 @@ PUBLIC GLXWindow
 glXCreateWindow(Display * dpy, GLXFBConfig config, Window win,
                 const int *attrib_list)
 {
+   warn_GLX_1_3(dpy, __func__);
+
    return CreateDrawable(dpy, (__GLcontextModes *) config,
                          (Drawable) win, attrib_list, X_GLXCreateWindow);
 }
@@ -662,6 +686,8 @@ glXCreateWindow(Display * dpy, GLXFBConfig config, Window win,
 PUBLIC void
 glXDestroyPixmap(Display * dpy, GLXPixmap pixmap)
 {
+   warn_GLX_1_3(dpy, __func__);
+
    DestroyDrawable(dpy, (GLXDrawable) pixmap, X_GLXDestroyPixmap);
 }
 
@@ -669,6 +695,8 @@ glXDestroyPixmap(Display * dpy, GLXPixmap pixmap)
 PUBLIC void
 glXDestroyWindow(Display * dpy, GLXWindow win)
 {
+   warn_GLX_1_3(dpy, __func__);
+
    DestroyDrawable(dpy, (GLXDrawable) win, X_GLXDestroyWindow);
 }