A　rapid,　simple,　and　practical　method　for　the　determination　of　four　of　the　most　used　thyreostatic　drugs　(methimazole,　2-thiouracil,　6-methyl-2-thiouracil,　and　6-propyl-2-thiouracil)　using　CE　coupled　to　electrochemiluminescence　detection　has　been　established,　based　on　the　electrochemiluminescence　enhancement　of　tris(2,2-bipyridyl)ruthenium(II)　with　these　analytes.　Parameters　that　affect　separation　and　detection　were　optimized.　Under　the　optimum　experimental　conditions,　the　four　analytes　could　be　well　separated　within　11　min　at　the　separation　voltage　of　16　kV　in　a　running　solution　containing　20　mM　phosphate　buffer　(pH　9.0)　and　1.0　×　10-4　M　Ru(bpy)3　2+,　with　a　solution　of　20　mM　phosphate　buffer　(pH　12.0)　containing　1.0　×　10　-4　M　Ru(bpy)3　2+　in　the　electrochemiluminescence　detection　cell.　The　detection　limits　for　methimazole,　6-methyl-2-thiouracil,　6-propyl-2-thiouracil,　and　2-　thiouracil　were　0.1,　0.05,　0.05,　and　0.01　μM,　respectively.　The　proposedmethod　was　applied　to　analyze　these　drugs　in　spiked　animal　feed　samples.　The　recoveries　were　88.2∼99.0　and　86.4∼98.7%　for　the　intraday　and　interday　analyses,　respectively.　The　RSDs　were　2.7∼4.8　and　1.8∼5.0%　for　the　intraday　and　interday　analyses,　respectively.　The　results　demonstrate　that　the　proposed　method　has　promising　applications　in　the　detection　of　thyreostatic　drugs　in　animal　feeds.　©　2014　WILEY-VCH　Verlag　GmbH　&　Co.　KGaA,　Weinheim.