The aim of this study was to determine the prevalence of asthma and other allergic disorders as well as the factors affecting these disorders in schoolchildren in Adana. This cross-sectional population-based study using the International Study of Asthma and Allergies in Childhood (ISAAC) protocol was carried out on 3164 school-children aged between 6-18 years during March to June 1997. There were 1521 (48.1%) boys and 1643 (51.9%) girls. The prevalence of asthma, allergic rhinitis and eczema in the 6-18 year-old children was found to be 12.6%, 13.6% and 8.3%, respectively. The prevalence of asthma was highest in 6-10 year-old school-children (14.7%), and lowest (6.0%) in 15-18 year-old children. The prevalence of asthma diagnosed by a doctor was 5.0%. The cumulative and current prevalences of wheezing were found to be 19.0% and 13.5%, respectively. The cumulative prevalence of allergic disorders was found to be 23.4%. The presence of domestic animals at home and dampness of the home were found to be important risk factors for asthma. Family histories of asthma, eczema, and diagnosis made by a doctor, and history of frequent sinusitis were found to be significantly higher in asthmatics.