<b>Background and Objective:</b> Leptin is a hormone produced by fat cells in adipose tissue that plays a biological role in metabolism, immune system control and energy flow regulation. The study's objective was to investigate serum leptin levels in PCOS females and determine how they are related to immunological and hormonal parameters. <b>Materials and Methods:</b> Thirty PCOS women were chosen for the study and compared to thirty healthy women as control samples, with both case and normal samples ranging in age from 18-36 years. WBC count, absolute numbers of neutrophils, lymphocytes, monocytes, eosinophils, leptin, Prolactin and serum IgA levels were measured. <b>Results:</b> The results showed the mean WBC, lymphocytes and eosinophil absolute numbers in PCOS women were significantly different. However, there was no significant difference in the absolute numbers of neutrophils and monocytes. The findings also revealed a significant increase in BMI, IgA, leptin and prolactin levels in PCOS when compared to controls. The results showed strong positive correlation coefficients between BMI and IgA (1.000**), WBC with neutrophils, lymphocytes and monocytes (0.797**, 0.790**, 0.712**), respectively and finally leptin and prolactin (0.474**). The same test, on the other hand, revealed an inverse correlation coefficient between BMI, IgA and prolactin (-0.376*, -0.376*, respectively with p<u><</u>0.05). <b>Conclusion:</b> A rise in the levels of the hormones leptin and prolactin, which were positively associated with the body mass index in women with PCOS, was found in the current study. The findings revealed that the hormones leptin and prolactin have an effect on some immune parameters in women with PCOS.