The prevalence of asthma is increasing everywhere in the world with consequent increases in the morbidity, mortality and economic burden of the disease particularly in developing countries. Numerous studies have shown an urban/rural discrepancy in the prevalence of asthma which has been attributed to urbanization, a westernized life-style and diet, air pollution and a “hygienic” life style. There have been relatively few studies from Nigeria in general and Northern Nigeria in particular on the prevalence of asthma or the urban/rural gradient in the prevalence of the disease. This study was undertaken to determine the prevalence of asthma in adolescents aged between 15 and 20 from 4 secondary schools in Kaduna town and 4 secondary schools in Kujama- a rural town, located about 60 kilometers from Kaduna. The prevalence of asthma was determined by means of a modified ISAAC study questionnaire and exercise-induced bronchospasm (EIB). The prevalence rate for asthma based on questionnaire responses was 10.6% in the urban sample and 6.3% in the rural sample with an overall rate of 8.5%. The prevalence rate of asthma based on EIB was15% in the urban sample and 5.6% in the rural sample with an overall rate of 10.3%. The study showed that both methods are useful tools for determining the prevalence of asthma. It also showed statistically higher prevalence rates among the urban sample as reported by other workers using similar method.