The　metabolites　of　nine　organophosphate　ester　(OPE)　flame　retardants　were　measured　in　180　urine　samples　collected　from　a　population　(including　adults　and　children)　in　western　Shanghai,　China,　using　liquid　chromatography-tandem　spectrometry　(LC-MS/MS).　The　total　urinary　concentrations　of　nine　OPE　metabolites　ranged　100-23800　pg/mL,　with　a　geometric　mean　(GM)　value　of　1450　pg/mL.　The　concentrations　of　alkyl-OPE　metabolites　(879　pg/mL)　were　approximately　an　order　of　magnitude　higher　than　those　of　aryl-OPE　(53.7　pg/mL)　and　chlorinated-OPE　metabolites　(52.7　pg/mL).　Diphenyl　phosphate　(DPHP),　diethyl　phosphate　(DEP),　di-n-butyl　phosphate　(DNBP),　bis(2-ethylhexyl)　phosphate　(BEHP),　and　bis(2-butoxyethyl)　phosphate　(BBOEP)　were　the　dominant　OPE　metabolites　found　in　urine.　The　results　showed　that　an　increase　in　age　was　associated　with　a　significant　decrease　in　urinary　DPHP　(r　=　-　0.278,　p　＜　0.01)　and　DNBP　(r　=　-0.314,　p　＜　0.01)　concentrations.　The　highest　concentrations　of　DPHP　(GM　=　80.7　pg/mL)　and　DNBP　(GM　=　16.9　pg/mL)　were　found　in　urine　from　people　living　in　homes　that　were　less　than　10　years　old.　The　urinary　DNBP　concentration　was　significantly　associated　with　self-reported　symptoms　of　allergy.　Our　result　establishes　baseline　value　for　OPE　exposure　in　a　population　in　China　for　comparison　in　future　studies.