To identify factors associated with asthma control in a multi-ethnic paediatric population. We interviewed 278 children with paediatrician diagnosed asthma (aged 7-17 years) and one of their parents. Asthma control was assessed with the Asthma Control Questionnaire (ACQ). Detailed information about sociodemographic variables, asthma medication, knowledge of asthma, inhalation technique and environmental factors were collected. Turkish and Moroccan parents were interviewed in their language of choice. Logistic regression analyses were used to identify correlates of asthma control. Of the 278 children, 85 (30.6%) were Dutch, 84 (30.2%) were Moroccan, 58 (20.9%) were Turkish and 51 (18.3%) were Surinamese. Overall, almost 60% had a status of well-controlled asthma, as indicated by the ACQ. Only 51 of the 142 (35.9%) Moroccan and Turkish parents had a good comprehension of the Dutch language. In logistic regression analyses the risk of having uncontrolled asthma was significantly higher among Surinamese children (OR 2.3; 95% CI 1.06-4.83), respondents with insufficient comprehension of the Dutch language (OR 2.3; 95% CI 1.08-4.78), children using woollen blankets (OR 9.8; 95% CI 1.52-63.42), and significantly lower among male (OR 0.5; 95% CI 0.31-0.91) and non-daily users of inhaled corticosteroids (OR 0.6; 95% CI 0.38-1.07). In conclusion, ethnicity as well as insufficient comprehension of the Dutch language appeared to be independent risk factors for uncontrolled asthma. Special attention should be given to children from immigrants groups for example by calling in an interpreter by physicians when comprehension is insufficient.