The objective in this study was to determine whether there was any relation between leptin and vascular endothelial growth factor (VEGF) in children with cyanotic and acyanotic heart anomalies. The study group consisted of 18 children with cyanotic congenital heart disease (CHD) and 20 age-adjusted children with acyanotic CHD as controls. Serum VEGF and leptin levels were determined by enzyme-linked immunosorbent assay (ELISA). The mean VEGF level was 149.25 +/- 42.93 pg/ml (range 80.66-217.00) in the cyanotic group and 88.18 +/- 20.94 pg/ml (range 48.44-112.71) in the acyanotic group (p<0.001). The mean leptin level was 7.55 +/- 1.46 ng/ml (range 4.08-10.25) in the cyanotic group and 6.89 +/- 1.43 ng/ml (range 2.67-8.57) in the acyanotic group (p=0.168). There was a significant positive correlation (r=0.723, p<0.001) between VEGF and leptin levels in the cyanotic group while there was no correlation (r=0.235, p=0.348) in the acyanotic group. Arterial oxygen saturation (SaO(2)) was negatively correlated (r= -0.625, p<0.001) with VEGF, but not correlated with leptin (r= -0.207, p=0.211) in the cyanotic group. There was no correlation between VEGF, leptin and SaO(2) in the acyanotic group. We conclude that it is likely that both VEGF and leptin have a role in the pathogenesis of angiogenesis in cyanotic CHD.