Cytokines play a critical and multifarious role in follicular maturation. Consequently, they may influence the pregnancy outcome in cycles of assisted reproduction. The aim of this study was to measure the levels of tumor necrosis factor-alpha (TNFalpha), vascular endothelial growth factor (VEGF) and leptin in serum and follicular fluids (FFs) from women undergoing controlled ovarian hyperstimulation (COH) for intracytoplasmic sperm injection cycles (ICSI). We tried to investigate their interrelationships and to evaluate them as predictive markers for the cycle's outcome. Seventeen women participated in this study. Male factor infertility was the only indication for ICSI cycles. For COH, the long agonist protocol with triptorelin and recombinant FSH was employed. Cytokines levels were evaluated by ELISA. Serum cytokine levels did not differ between pregnant and non-pregnant women. FF-VEGF levels were significantly elevated in non-pregnant women (722.2+/-1093.2 pg/ml) as compared to pregnant women (290.3+/-259.8 pg/ml). Leptin concentrations were also significantly higher in FFs of non-pregnant women (682.6+/-625.1 ng/ml) than those of pregnant women (231.6+/-286.5 ng/ml). There were significant positive correlations between FF-leptin and age, as well as between FF-leptin and FF-VEGF concentrations. It was concluded that elevated FF-leptin and VEGF levels are associated with failure of conception in IVF cycles and may serve as markers in clinical practice.