Aim To investigate the relationship between plasma concentrations of leptin and the severity of coronary artery stenosis,obesity.Methods According to coronary angiography,73 coronary atherosclerosis(As) patients and 20 healthy controls were enrolled in the present study.The plasma levels of leptin were determined and the relationship between leptin level and Gensini score and body mass index(BMI) was analyzed.Results As the Gensini score increased,the leptin levels increased(p<0.05).The plasma leptin levels in control group,Gensini score 1～30,31～90 and >90 groups were 0.52±0.12 μg/L,0.61±0.15 μg/L,0.77±0.13 μg/L and 0.93±0.13 μg/L,respectively.The plasma concentrations of leptin in As patients were significantly correlated with Gensini score(r=0.643,p<0.01).As the BMI increased,the leptin levels increased(p<0.05).The plasma leptin levels of normal weight,overweight,obesity groups were 0.59±0.17 μg/L,0.75±0.16 μg/L and 0.89±0.11 μg/L,respectively.Conclusions The plasma concentrations of leptin is significantly related to the severity of coronary artery stenosis and obesity.It suggests that leptin may be involved in the development of As.