diff --git a/debian/control b/debian/control
index d3840463d5..f5215e540f 100644
--- a/debian/control
+++ b/debian/control
@@ -4,6 +4,7 @@ Priority: optional
 Build-Depends: 
 	debhelper (>= 9),
 	ghc (>= 7.4),
+	libghc-mtl-dev (>= 2.1.1-1),
 	libghc-missingh-dev,
 	libghc-hslogger-dev,
 	libghc-pcre-light-dev,
diff --git a/doc/bugs/3.20121112_build_fails_on_Ubuntu_12.04.mdwn b/doc/bugs/3.20121112_build_fails_on_Ubuntu_12.04.mdwn
index 9d743209bf..cd08976497 100644
--- a/doc/bugs/3.20121112_build_fails_on_Ubuntu_12.04.mdwn
+++ b/doc/bugs/3.20121112_build_fails_on_Ubuntu_12.04.mdwn
@@ -90,3 +90,8 @@ Ubuntu 12.04 (current "long term support", all packages up to date)
 Please provide any additional information below.
 
 No idea how important this is for git-annex in general but reporting in case it is. Thank you for working on git annex!
+
+> I was able to reproduce this build error when I force installed
+> an old version of the haskell mtl library. So git-annex needs version
+> 2.1.1 to build, and I have adjusted the build dependencies appropriately.
+> [[done]] --[[Joey]] 
diff --git a/doc/install/fromscratch.mdwn b/doc/install/fromscratch.mdwn
index 49dd1302e3..1aebc68a28 100644
--- a/doc/install/fromscratch.mdwn
+++ b/doc/install/fromscratch.mdwn
@@ -3,6 +3,7 @@ quite a lot.
 
 * Haskell stuff
   * [The Haskell Platform](http://haskell.org/platform/) (GHC 7.4 or newer)
+  * [mtl](http://hackage.haskell.org.package/mtl) (2.1.1 or newer)
   * [MissingH](http://github.com/jgoerzen/missingh/wiki)
   * [pcre-light](http://hackage.haskell.org/package/pcre-light)
   * [utf8-string](http://hackage.haskell.org/package/utf8-string)
diff --git a/git-annex.cabal b/git-annex.cabal
index eb5f775118..c79b305f3c 100644
--- a/git-annex.cabal
+++ b/git-annex.cabal
@@ -55,7 +55,7 @@ Flag DNS
 Executable git-annex
   Main-Is: git-annex.hs
   Build-Depends: MissingH, hslogger, directory, filepath,
-   unix, containers, utf8-string, network (>= 2.0), mtl,
+   unix, containers, utf8-string, network (>= 2.0), mtl (>= 2.1.1),
    bytestring, old-locale, time,
    pcre-light, extensible-exceptions, dataenc, SHA, process, json, HTTP,
    base (>= 4.5 && < 4.7), monad-control, transformers-base, lifted-base,
@@ -115,10 +115,11 @@ Test-Suite test
   Type: exitcode-stdio-1.0
   Main-Is: test.hs
   Build-Depends: testpack, HUnit, MissingH, hslogger, directory, filepath,
-   unix, containers, utf8-string, network, mtl, bytestring, old-locale, time,
-   pcre-light, extensible-exceptions, dataenc, SHA, process, json, HTTP,
-   base (>= 4.5 && < 4.7), monad-control, transformers-base, lifted-base,
-   IfElse, text, QuickCheck >= 2.1, bloomfilter, edit-distance, process
+   unix, containers, utf8-string, network, mtl (>= 2.1.1), bytestring,
+   old-locale, time, pcre-light, extensible-exceptions, dataenc, SHA,
+   process, json, HTTP, base (>= 4.5 && < 4.7), monad-control,
+   transformers-base, lifted-base, IfElse, text, QuickCheck >= 2.1,
+   bloomfilter, edit-distance, process
   Other-Modules: Utility.Touch
   Include-Dirs: Utility
   C-Sources: Utility/libdiskfree.c