OBJECTIVE To compare DHEAS levels among subjects with and without PCOS, evaluating differences between lean-PCOS or obese-PCOS phenotype for insulin resistance, anthropometric indices, glycemic and lipid parameters. METHODS Descriptive study. Study Place and Duration of Study: PNS Hafeez Naval Hospital, Islamabad, Pakistan, from January 2018 to August 2019. METHODS Three hundred and twenty-eight subjects were included in the study for evaluation. PCOS was defined as per Rotterdam criteria, while insulin resistance, anthropometric measurements, various hormonal and biochemical analyses were carried out as per standard protocols. Hirsutism was calculated as per modified Ferrimen Gallwey score and free androgen index (FAI) was calculated using formula as: FAI = [(Total testosterone/Sex hormone binding globulin (SHBG)] x100. These subjects underwent clinical biochemical evaluation and were segregated into 2 groups: lean-PCOS and obese-PCOS.   Results: DHEAS levels were higher in subjects with PCOS [(171.50) (111.75-244.25) ug/dl], n=164] than in subjects without PCOS [(130.50) (78.95-189.75) ug/dl, n=164, p<0.001]. Area under curve (AUC) in diagnosing PCOS was highest for modified FG score [0.802, p<0.001], followed by FAI [0.785, p<0.001]. Total testosterone [0.743, p<0.001] and DHEAS [0.637, p<0.001]. DHEAS levels were found to be inversely related to age, anthropometric indices, glycemia, dyslipidemia, nephropathy and reproductive hormones. The DHEAS in lean-PCOS was higher than obese female subjects with or without PCOS. CONCLUSIONS DHEAS levels were high in lean-PCOS in comparison to obese-PCOS and non-PCOS females. However, receiver operating curve (ROC) analysis showed DHEAS as a weaker marker for diagnosing PCOS than FAI and modified FG score. Key Words: DHEAS, Polycystic ovarian syndrome (PCOS), Homeostasis model assessment for insulin resistance (HOMAIR), Rotterdam criteria, Free androgen index.