Smoking cessation is associated with transient increases in body weight. Leptin and ghrelin are known to be major mediators of appetite, weight and the reward pathway. Therefore, this study assessed the changes in the plasma leptin and ghrelin level and their relationship with the body weight and appetite after smoking cessation in the Korean population. Eighteen subjects, who had stopped smoking for 2 months were enrolled in this study. The body mass index (BMI), body fat mass (BFM), waist-hip ratio (WHR), weight and appetite were measured before and after smoking cessation. In addition, the plasma leptin and ghrelin levels were measured. The BMI, BFM, WHR, weight and appetite were significantly higher than baseline in those who had gave up smoking for 2 months (p<0.05). The plasma leptin concentration increased and the plasma ghrelin level decreased after smoking cessation. The change in the leptin level was positively correlated with the change in the body mass index and body fat mass. These results do not support the direct mediation of the leptin-ghrelin-neuropeptide Y (NPY) system on weight gain after smoking cessation. It appears that weight and appetite is regulated by a more complicated mechanism after smoking cessation.