Aim of this study is evaluation the effect of aerobic exercise and its duration on pulmonary function in young healthy adults. Pulmonary function tests were done before and after aerobic exercise of 6 weeks duration in 46 healthy adults.  Mean value ± SD of  FVC (3.74 ± 0.44 liters), FEV1(3.29 ± 0.35 liters), FEV1/FVC (89.30 ± 4.54 liters) before the running and after the running it became FVC  (3.77  ±  0.45 liters), FEV1 (3.33   ± 0.40 liters), FEV1/FVC (89.65  ±  4.96 liters)  respectively. P value are FVC (0.32), FEV1 (0.16) and  FEV1/FVC (0.50)  which are not statically significant. Aerobic exercise of more than 6 weeks duration are required to bring change in the Lung functions.