AIM: The study aimed to determine prevalence and severity of asthma, rhinitis and eczema in Maputo, Mozambique. METHODS: The International Study of Asthma and Allergies (ISAAC) protocol was applied in 27 schools in urban, suburban and semi-rural areas. RESULTS: A total of 2630 completed questionnaires were obtained from students aged 13-14 years, and 2383 from schoolchildren aged 6-7 years. The prevalence of current asthma was 13.3% in the two groups, the prevalence of rhinoconjuctivitis and eczema was 23% and 10% in teenagers and 8.8% and 8.5% respectively in children 6-7 years old. Overall, 35% of the adolescents and 23.8% of children were found to have at least one atopic condition or asthma in the last year. In symptomatic adolescents, the conditions were: rhinoconjuctivitis (41.3%), asthma (20%) and eczema (12.4%). In symptomatic children, asthma was the principal condition (36.2%), followed by eczema (20.3%) and rhinoconjunctivitis (19.1%). In adolescents, asthma was more frequently associated with rhinoconjuctivitis (28%). About 4% of all surveyed children had three atopic conditions associated. In adolescents, past year rhinitis was more frequent and severe in the urban area. Hay fever was commoner in the semi-urban area. Eczema was significantly more recurrent in suburban and semi-rural area. Exercise-induced wheeze, nocturnal cough and ever asthma were more reported in children of suburban area. CONCLUSION: Asthma and allergic diseases are important public health problems in Maputo and improvement in prevention and management plans are required.