The aim of this study was to determine the prevalence of symptoms suggestive of asthma in children aged 7-14 years in Ankara, Turkey. For this purpose, the recently developed ISAAC (International Study for Asthma and Allergies in Childhood) questionnaire supplemented with six additional questions was issued to parents of 3154 primary school children from 12 schools. A separate page with questions regarding risk factors was also added to the questionnaire. The response rate was 88.3%. The cumulative and 12-month prevalence of wheezing were 14.4 and 4.7% respectively. The prevalence of physician-diagnosed asthma was 8.1%. A family history of atopy was found to be the strongest risk factor for having ever had wheezing (odds ratio (OR) = 2.89, 95% confidence interval (CI) = 2.32-3.60), wheezing in the past 12 months (OR = 3.21, CI = 2.21-4.67), and severe attack (OR = 2.41, CI = 1.36-4.25). Passive smoking was a risk only for having ever had wheezing (OR = 1.33, CI = 1.03-1.76). Increasing age was associated with a lower risk of current wheezing (OR = 0.85, CI = 0.81-0.90) and severe attack (OR = 0.77, CI = 0.67-0.88). Gender, socio-economic level and pet ownership did not appear to be risk factors for asthma-related symptoms. This study, the first epidemiological survey in Ankara, Turkey, using the ISAAC protocol, clearly shows that symptoms suggestive of asthma, albeit lower than in most European countries, are quite common and constitute a major health problem in Turkey.