diff --git a/doc/functions.xml b/doc/functions.xml
index 2aae3cfb2ae..aec8a57c21a 100644
--- a/doc/functions.xml
+++ b/doc/functions.xml
@@ -85,6 +85,44 @@ in ...
+
+ <pkg>.overrideDerivation
+
+
+ The function overrideDerivation is usually available for all the
+ derivations in the nixpkgs expression (pkgs).
+
+
+ It is used to create a new derivation by overriding the attributes of
+ the original derivation according to the given function.
+
+
+
+ Example usage:
+
+ mySed = pkgs.gnused.overrideDerivation (oldAttrs: {
+ name = "sed-4.2.2-pre";
+ src = fetchurl {
+ url = ftp://alpha.gnu.org/gnu/sed/sed-4.2.2-pre.tar.bz2;
+ sha256 = "11nq06d131y4wmf3drm0yk502d2xc6n5qy82cg88rb9nqd2lj41k";
+ };
+ patches = [];
+});
+
+
+
+ In the above example, the name, src and patches of the derivation
+ will be overridden, while all other attributes will be retained from the
+ original derivation.
+
+
+
+ The argument oldAttrs is used to refer to the attribute set of
+ the original derivation.
+
+
+
+