The objective of this study was to investigate the effects of indoor air pollution on respiratory function of children (aged 7-15 years). The study took place at Ashok Vihar, an urban locality in the northwest part of Delhi during the summer months of June and July 2004. The team did house visits. The questionnaire, administered at the house itself, asked about the history of smoking in the family, type of cooking fuel used, duration of cooking, ventilation and lighting at the cooking place, and other confounders. In total, 441 children (59% male, 41% female) between ages 7 and 15 years were considered for the study, and a detailed profile was collected. Clinical examination with special reference to respiratory system was done. Pulmonary function tests/peak expiratory flow rates of each child were measured. Indoor air pollutant (suspended particulate matter, SO(2), NO(2)) was measured, and the effect of these pollutants on the children's respiratory function was analyzed. The respiratory health profile suggests that children had cough, sputum production, shortness of breath, wheezing, common cold, and throat congestion. Indoor SO(2) , NO(2), and suspended particulate matter levels were high in houses where there was a family history of smoking. SO(2) level was significantly high according to occupancy per room. NO(2) and suspended particulate matter levels were significantly high in houses where children had respiratory problems. It is concluded that indoor air pollution had an association with respiratory function of children.