Bronchial asthma is one of the most common chronic diseases of childhood. In recent years a consistent increase in the prevalence, and concomitantly, in the social and economic impact of the disease, has been reported. In order to provide data for the cost of pediatric asthma and its determinants in Turkish children, a study was performed in a single outpatient clinic, which encompasses a questionnaire-guided interview and retrospective evaluation of the last year files. From the 183 patients enrolled, most were males (65.6%) and atopics (63.5%), with a disease severity of mild intermittent (67.7%). Mean annual total costs per patient was US $991.7 +/- 73.2 (median = 688.8) and the largest proportion of the direct costs was due to outpatient clinic costs (48.5%). Mean cost of any hospitalization per patient was US $955.5 +/- 16.5. In multivariate analysis, the disease severity, current use of preventive drugs and current use of emergency sevice and/or current hospitalization appeared to be the main determinants of direct costs. Adequate control of the disease plays a key role in decreasing the total direct costs of pediatric asthma although it increases the medication and outpatient costs.