diff --git a/rebar.config b/rebar.config
index 99ed2cd..350bc29 100644
--- a/rebar.config
+++ b/rebar.config
@@ -53,7 +53,7 @@
                                      "/njs /njh /nfl /ndl & exit /b 0"} % silence things
                                    ]}
                      ]},
-             {eqc, [{erl_opts, [{parse_transform, eqc_cover}]},
+             {eqc, [{erl_opts, [{parse_transform, eqc_cover}, {d, 'EQC'}]},
                     {extra_src_dirs, ["quickcheck"]}    %% May not be called eqc!
                    ]}
             ]}.