A　simple,　sensitive　and　reproducible　method　using　microemulsion　electrokinetic　chromatography　(MEEKC)　-field　amplified　sample　injection　(FASl)　was　developed　for　the　analysis　of　nine　narcotics　(morphine,　codeine,　naloxone,　heroin,　thebaine,　cocaine,　pethidine,　fentanyl　and　methadone)　in　urine.　In　the　MEEKC　method,　sodium　dodecyl　sulfate　(SDS),　1-butanol　and　ethyl　acetate　were　used　as　surfactant,　co-surfactant　and　organic　solvent,　respectively.　The　effects　of　the　acidity　and　concentration　of　borate　buffer,　SDS,　1-butanol　and　ethyl　acetate　contents　were　investigated.　The　optimum　concentrations　(by　mass　fraction)　of　microemulsion　system　were　0.　6%　SDS,　1.　2%　1-butanol,　0.　6%　ethyl　acetate　and　97.　6%　10　mmol/L　Na　2B　4O　7　buffer　(pH　9.　5).　The　applied　voltage　was　25　kV.　FASI　was　coupled　with　the　MEEKC　method　to　increase　the　sensitivity.　Under　the　optimum　conditions,　the　nine　narcotics　were　baseline　separated　within　15　min　and　the　detection　limits　\S/N=3/　were　in　the　range　of　0.　3　-8.　0　μg/L.　The　spiked　recoveries　in　urine　samples　were　between　79.　4%　and　119.　9%　with　the　intraday　relative　standard　deviations　(RSDs)　less　than　5.　5%.　The　developed　method　has　been　successfully　applied　to　the　analysis　of　methadone　in　the　samples　from　in　vitro　metabolism　study.