diff --git a/doc/gendoc.py b/doc/gendoc.py
--- a/doc/gendoc.py
+++ b/doc/gendoc.py
@@ -7,6 +7,7 @@ from mercurial import demandimport; dema
 from mercurial.commands import table, globalopts
 from mercurial.i18n import _
 from mercurial.help import helptable
+from mercurial import extensions
 
 def get_desc(docstr):
     if not docstr:
@@ -111,5 +112,15 @@ def show_doc(ui):
         ui.write(doc)
         ui.write("\n")
 
+    # print extensions
+    underlined(_("EXTENSIONS"))
+    ui.write('\n')
+    for name in sorted(extensions.listexts('../hgext')):
+        ui.write('.. _%s:\n\n' % name)
+        doc = extensions.doc(name).splitlines()
+        synopsis, rest = doc[0], doc[1:]
+        ui.write("``%s: %s``" % (name, synopsis))
+        ui.write('%s\n\n' % '\n    '.join(rest))
+
 if __name__ == "__main__":
     show_doc(sys.stdout)