Background: Polycystic ovarian syndrome (PCOS), the most common endocrinopathy of women in the reproductive age group seems to be adversely affected by associated thyroid dysfunction. Both pose independent risks of ovarian failure and pregnancy related complications. Aim: to investigate the prevalence and etiology of different thyroid disorders in PCOS patients. Material and methods: This cross-sectional study conducted in Anugrah Narayan Magadh Medical college and Hospital, Gaya, Bihar, India, for 12 months. Total 80 female patients in the age group between 18 and 35 years, diagnosed of PCOS were included in the study. Diagnosis of PCOS was done by Rotterdam classification. Hirsutism was graded by Ferriman– Gallwey score. Based on this score pattern and other clinical tests, hirsutism can be evaluated as mild, moderate or severe. Fasting blood sugars, fasting insulin levels, serum luteinizing hormone (LH), follicle stimulating hormone (FSH), TSH, serum testosterone, dehydroepiandrosterone, and serum prolactin were done. Results: The mean age of the patients with PCOS was 21.5±4.77 years. All the patients had some form of menstrual irregularities either oligo menorrhea, irregular menses orsecondary amenorrhea.A total of 60(75%) had body mass index ≥25 kg/m. Clinical hirsutism was present in significant number 72.5% of cases (Ferriman–Gallwey score >7). LH/FSH ratio of more than 2 was found in 62.5% of the cases. Homeostatic model assessment IR (HOMA-IR) was calculated from fasting blood sugar and fasting insulin levels, and 56 subjects (70%) were insulin resistant. The mean TSH levels in subjects were 4.39±1.91.