Background: Polycystic ovary syndrome (PCOS) is the most common endocrine disorder among women of fertile age. Insulin can stimulate ovarian androgen production in normal women and in women with PCOS. Leptin levels were reduced among women with PCOS treated with insulin sensitizers. Aim: This study aims to investigate the serum levels of insulin and leptin in and their relationship with the endocrine and metabolic peculiarities of PCOS. Subjects and Methods: The study was carried out on 125 women during the reproductive age group, had primary infertility and diagnosed as having PCOS according to Rotterdam criteria. Patients were recruited from Tanta University Hospital, during the period May 2011 to December 2012. Cases were classified into two groups: Patient’s group comprised 75 women having PCOS and control group entailing 50 normal fertile healthy women. All women were subjected to: History taking, clinical examination, assessment of body mass index (BMI), ultrasonographic examination and hormonal assay to estimation serum leptin, insulin, follicle stimulating hormone, luteinizing hormone, progesterone and free testosterone value. Statistical analysis was performed by Statistical Product and Service Solutions (IBM, USA) version 10.0. Student t‑test was used to compare numerical variables while correlation was performed to determine the relationship between the variables. The value of P < 0.05 was taken as significant. Results: We found a significant positive correlation between leptin, BMI, age and a trivial upbeat correlation between leptin and insulin. The most interesting result is the significant positive correlation between insulin and leptin. Conclusion: There is a link between elevated serum leptin and insulin levels to obesity in PCOS suggesting that most probably they are responsible for the complicated picture of PCOS in obese patients.