ObjectiveTounderstandthetrendsandepidemiologicalcharacteristicsofsexuallytransmitteddiseases(STDs)inChinaandprovidescientificbasisformakingcontrolstrategies.MethodsDuringtheperiodof1991～2001,thecase-reportingdataof8kindsofnotifiableandmonitoringSTDs,collectedfrom31provinces,autonomousregionsandmunicipalities,wereanalyzedwithepidemiologicalmethods.Results①Epidemictrends:Duringthisperiod,theincidenceof8kindsofSTDssteadilyincreasedfrom175528(15.48per100000population)in1991to859040(68.91per100000population)in2000.Theaverageannualgrowthofincidencewas19.30%,witharangeof2.59%～36.88%.However,thereportedcasesin2001were795612withadecreaseof7.38%comparedwiththosein2000,anditwasthefirstdecreasesinceSTDcaseswerereportedfrom1987.②Geographicaldistribution:Thehigh-incidenceareasweretheZhujiangRiverDelta,YangtzeRiverDelta,MinjiangRiverValley,NortheasternChina,andBeijing,Tianjin,andChongqingManicipalities,withtheincidencerateofover70～100casesper100000populationafter1997,andtherewereveryhighratesofincidenceover1000casesper100000populationinsomeareas.Thelow-incidenceareaswerenorthChina,partsofCentralChina,NorthwesternChinaandSouthwesternChina,withtheincidenceratesoflowerthan30～50per100000population.③Populationdistri-bution:Themaletofemaleratiodecreasedfrom1.60∶1～1.69∶1intheearly1990sto1.35∶1～1.40∶1inthelate1990s.STDincidencerateswerehighestinthe20～39agegroup,andthereportedSTDcasesofthisagegroupaccountedforover80%oftotalcases.ConclusionSexuallytransmitteddiseasesinChinahavebecomeaseriouspublichealthproblemandtheeffectiveinterventionprogrammesagainstSTDsmustbeimplementedacrossthecountry.