A liquid chromatography-tandem mass spectrometric(LC-MS/MS) method was established for the determination of five androgens,ie. dehydroepiandrosterone sulfate(DHEAS),androstenedione(A4),testosterone(T),17 hydroxyprogesterone(17 OHP) and dihydrotestosterone(DHT),in serum.The serum samples were extracted by solid phase extraction after protein precipitation,then separated on an Agela Venusil MP C18 column(30 mm×50 mm,3 μm) by gradient elution using methanol containing 01% formic acid and water with 002% formic acid as mobile phases,finally detected with electrospray ionization in positive or negative mode under multiple reaction monitoring(MRM) mode.As a result,there were good linear relationships for five androgens in their respective mass concentration ranges with correlation coefficients(r2) more than 0995,and the recoveries ranged from 960% to 105%.The intra and inter assay precision values for all androgens were less than 10%.The limits of quantitation for DHEAS,A4,T,17 OHP and DHT were 500,005,005,0025,0025 ng/mL,respectively.The method is rapid,accurate and sensitive,and could satisfy the requirements for clinical determination of serum androgens in patients with polycystic ovary syndrome(PCOS).