Polycystic ovarian syndrome (PCOS) is a common medical problem that causes infertility to women. The objectives of the present study were to investigate the effect of socio-demographic, clinical and hormonal factors on PCOS among infertile women in Rajshahi, Bangladesh. The present cross-section study was carried out in the Motherland Infertility Centre and Hospital in Rajshahi, Bangladesh. The data was collected from 324 infertile women by using systematic sampling. The results revealed that about half (48.1%) of infertile women were young adults (aged 21-25 years). More than 64% infertile women came from urban areas. A remarkable number of infertile women (14.8%) passed their conjugal life more than 10 years. Among infertile women, 56.1% completed their secondary and higher education and 79% women were housewife. This study demonstrated that most of the infertile women (65.4%) were over nourished. More than 78% and 25.9% women experienced irregular and painful menstrual cycle and 61.7% women had oligomenorrhoea. Most of the women (95%) did not have hirsutism, and most of the respondents (96.3%) did not have occurrence abortion. Among infertile women, 25.3% and 48.1% had raised (>10 mlU/ml) serum FSH and raised (>10 mlU/ml) serum LH respectively, which was not 1:1 ratio. 30.2% infertile women had raised (>498 mlU/ml) serum prolactin and the mean value was 708.17 mlU/ml which was greater than 700 mlU/ml. More than 34% respondents had high (>3.6 mlU/ml) serum TSH and their mean value was 6.24 mlU/ml. Therefore, this study suggests that obesity, menstrual disturbances and hormonal level are most important risk factors for PCOS patients among infertile women in Rajshahi, Bangladesh.