Introduction and Aim: Polycystic Ovarian Syndrome (PCOS) manifests with menstrual irregularities, infertility, galactorrhoea and hirsutism. Hormonal irregularities are found to be the pathogenesis behind PCOS. The study was aimed to evaluate whether obesity is associated with serum prolactin and insulin levels in PCOS women.    Materials and Methods: This case control study was conducted in a tertiary care hospital in Chennai. Control group included 30 apparently healthy women and cases included 30 PCOS patients, diagnosis based on Rotterdam criteria. The individuals were of 20-40 years of age in both the groups. The serum prolactin and insulin were analysed by ELISA. The obtained data were checked for normality of distribution and subjected to statistical analysis. Receiver Operating Characteristics (ROC) curve was done. Statistical analyses were performed using SPSS version 16.0. P less than 0.05 was considered statistically significant.   Results: The median and interquartile range (IQR) of serum insulin were 11.5 (1.8-70) and 5 (1.8-44) mIU/L in cases and controls respectively. The cut-off level of insulin was 7.0 mIU/L. The median and IQR of serum prolactin were 12.5 (4.5-53.0) and 12 (3.5-20) ng/mL in cases and controls respectively. BMI was positively correlated with age of the participants and prolactin.   Conclusion: PCOS is prevalent among obese reproductive individuals. Insulin was markedly elevated in PCOS individuals. Insulin resistance alters levels of luteinizing hormone and sex hormone binging globulins. Hyperprolactinemia is associated with anovulation or oligoovulation, galactorrhoea and hirsutism. In obese PCOS women, prolactin and insulin could be diagnostic markers of PCOS.