diff --git a/doc/reference/cogl/Makefile.am b/doc/reference/cogl/Makefile.am
index 0d08a36db..82b96928f 100644
--- a/doc/reference/cogl/Makefile.am
+++ b/doc/reference/cogl/Makefile.am
@@ -12,7 +12,7 @@ AUTOMAKE_OPTIONS = 1.6
 DOC_MODULE=cogl
 
 # The top-level SGML file. You can change this if you want to.
-DOC_MAIN_SGML_FILE=$(DOC_MODULE)-docs.sgml
+DOC_MAIN_SGML_FILE=$(DOC_MODULE)-docs.xml
 
 # The directory containing the source code. Relative to $(srcdir).
 # gtk-doc will search all .c & .h files beneath here for inline comments
diff --git a/doc/reference/cogl/cogl-docs.sgml b/doc/reference/cogl/cogl-docs.xml
similarity index 100%
rename from doc/reference/cogl/cogl-docs.sgml
rename to doc/reference/cogl/cogl-docs.xml