diff --git a/include/agner_spec.hrl b/include/agner_spec.hrl
index 8c4b32a..b0e0dbb 100644
--- a/include/agner_spec.hrl
+++ b/include/agner_spec.hrl
@@ -12,6 +12,10 @@
         {git, url(), git_ref()} |
         {hg, url(), hg_rev()}.
 
+-type agner_spec_requirement() :: {agner_package_name(), agner_package_version_string()} |
+                                  agner_package_name().
+
+
 -type agner_spec_property_name() :: {name, string()}.
 -type agner_spec_property_description() :: {description, string()}.
 -type agner_spec_property_keywords() :: {keywords, list(string())}.
@@ -28,6 +32,8 @@
 -type agner_spec_property_applications() :: {applications, list(atom())}.
 -type agner_spec_property_caveats() :: {caveats, string()}.
 -type agner_spec_property_url() :: {url, agner_download_url()}.
+-type agner_spec_property_deps_dir() :: {deps_dir, directory()}.
+-type agner_spec_property_requires() :: {requires, list(agner_spec_requirement())}.
 -type agner_spec_code_paths() :: {code_paths, [directory()]}.
                                                              
 
@@ -46,6 +52,8 @@
                                agner_spec_property_applications() |
                                agner_spec_property_caveats() |
                                agner_spec_property_url() |
+                               agner_spec_property_deps_dir() |
+                               agner_spec_property_requires() |
                                agner_spec_code_paths().
 
 -type agner_spec() :: list(agner_spec_property()).
diff --git a/src/agner_main.erl b/src/agner_main.erl
index 55b79e6..9947fed 100644
--- a/src/agner_main.erl
+++ b/src/agner_main.erl
@@ -350,6 +350,19 @@ handle_command(fetch, Opts) ->
             io:format("~p~n",[agner:fetch(Spec,Version,
                                     Directory)]),
 
+            Requires = proplists:get_value(requires, Spec, []),
+            DepsDir = filename:join(Directory, proplists:get_value(deps_dir, Spec, "deps")),
+            lists:foreach(fun ({ReqName, ReqVersion}) ->
+                                  io:format("[Building dependency: ~s -v ~s]~n", [ReqName, ReqVersion]),
+                                  handle_command(fetch, [{package, ReqName},{version, ReqVersion},
+                                                         {directory, filename:join(DepsDir,ReqName)}|
+                                                         proplists:delete(spec,Opts)]);
+                              (ReqName) when is_list(ReqName) ->
+                                  io:format("[Building dependency: ~s]~n", [ReqName]),
+                                  handle_command(fetch, [{package, ReqName},{version, "@master"},
+                                                         {directory, filename:join(DepsDir,ReqName)}|
+                                                         proplists:delete(spec, Opts)])
+                         end, Requires),
                           
             case proplists:get_value(caveats, Spec) of
                 undefined ->