Aim The aim was to study serum Leptin level in obese and non-obese asthmatic patients and its change during acute attack and in remission and its relation to the changes in pulmonary functions. Methods The study was carried out on fifty five participants 40 asthmatics and 15 control subjects and both are divided according to body mass index (BMI) into obese [(BMI ˃ 30 kg/m² ), 20 asthmatic and 8 control subjects] and no-obese [(BMI˂25 kg/m²), 20 asthmatic and 7 control subjects]. All participants were subjected to calculation of BMI, pulmonary function tests, morning serum Leptin level estimation (after at least 8 hours of fasting). Results Serum leptin level (mean in ng/ml) in obese control (64 ng/ml) and obese asthmatic (80.4 ng/ml during exacerbation and 92.9 during remission) subjects was significantly higher than that in non-obese control (6.3 ng/ml) and non-obese asthmatic (33.8 ng/ml during exacerbation and 48.8 during remission) subjects. There was a significant (r=-0.456 and p=