A hospital based cross-sectional study was conducted from March 2005 to April 2006 to evaluate the distribution of various respiratory diseases by spirometry. A total of 228 consecutive cases referred for spirometry were included of which 65% were male and 35% female. COPD was the commonest referral diagnosis (40%) followed by the diagnosis of shortness of breath (22%). After spirometry the prevalence of COPD was 42%, Asthma 23.5%, Restrictive disease 3.1% and mixed obstructive and restrictive disease 3.5%. 25% of the sample population was smokers and 22% ex-smokers. Hence we conclude that spirometry is a very useful diagnostic tool for preliminary diagnosis of respiratory diseases and should be used more by general practitioners and physicians to make their diagnosis and therapy more scientific.