OBJECTIVE: The present study was carried out to evaluate lung functions and develop prediction equations in Indian boys. SUBJECTS: 1555 normal healthy schoolboys from Hyderabad city who were in the age group of 5 to 15 years were selected for the present study. DESIGN: The anthropometric parameters such as height, sitting height, weight, and chest circumference were measured and body surface area (BSA) and percent body fat (% Fat) were derived. The lung functions studied were FEV1, FVC, FEV1% and PEFR. RESULTS: The height, sitting height, weight, BSA, chest circumference, body fat as well as FEV1, FVC, FEV1 % and PEFR were comparable with Indian boys. The height for age, weight for age and weight for height were found to be lower than 50th percentile of NCHS standards in the subjects studied. Similarly the lung function values of the study population were found to be lower than the values of corresponding western population. CONCLUSION: Regression equations were derived to predict FEV1, FVC and PEFR using physical characteristics. Height, chest circumference and fat free mass were the best predictors for FEV1, FVC, and PEFR. Age, height, sitting height, weight, chest circumference and fat free mass showed significant association with lung functions.