The present invention provides compounds useful as agents for the prevention or treatment of a sex hormone-dependent disease or the like. That is, the present invention provides fused heterocyclic derivatives represented by the following general formula (I) which has a GnRH antagonistic activity, pharmaceutical compositions containing the same, medicinal uses thereof and the like. In the formula (I), rings A is 5-membered cyclic unsaturated hydrocarbon or 5-membered heteroaryl； RA is halogen, alkyl, alkenyl, alkynyl, carboxy, alkoxy, carbamoyl, alkylcarbamoyl, etc.； ring B is aryl or heteroaryl； RB is halogen, alkyl, carboxy, alkoxy, carbamoyl, alkylcarbamoyl, etc.； E1 and E2 are oxygen atom, etc.； Q is hydrogen atom, alkyl, alkylsulfonyl, acyl, etc.； X is -(alkylene)-Z, —CO—Y, —SO2—Y, etc. (in which Y is Z or amino, etc.； Z is cycloalkyl, heterocycloalkyl, aryl, heteroaryl, etc.
