Background: Cigarette smoking causes airflow limitation with lung hyperinflation being the primary cause of chronic obstructive pulmonary disease (COPD). Most of the smokers have subclinical parenchymal lung disease. Early diagnosis and treatment decrease the rate of morbidity and mortality. Aim and objective: The aim of our present study was to assess the forced expiratory volumes like forced vital capacity (FVC), forced expiratory lung volume in 1 second (FEV1), percentage of FEV1 (FEV1%), forced expiratory flow during 25-75% of expiration (FEF 25-75%) and peak expiratory flow rate (PEFR) in asymptomatic smokers. Method: The study was conducted in 50 asymptomatic smokers using computerized spirometer and the data was compared and analysed with the values of 50 non-smokers. Result: all the forced expiratory lung volumes were decreased in smokers when compared to non-smokers. Conclusion: Cigarette smoking cause a definite deterioration in lung function though the subjects were asymptomatic.