The relationship between the severity and duration of asthma and psychological adjustment was investigated in 29 children with mild and 31 children with moderately severe asthma, who were compared with 60 healthy control children. The severity of asthma was evaluated using the Pearlman-Bierman classification. Psychological adjustment was measured using the Achenbach Child Behavior Checklist (CBCL) and a semi-structured interview. The results of the interviews indicated that regressive symptoms such as clinging, childish behaviour, dependence, and a demanding nature were widespread. Using the illness in the service of achieving other aims was also common in the asthmatic children. CBCL total problem behaviour scores, social competency, and broad band scores were significantly higher in the asthmatic group than the control sample. Problem scores for asthmatic children were significantly correlated with parental friction at home, unsatisfactory relationships with siblings and other health problems in children. However, neither the CBCL total problem scores nor the social competency scores were correlated with the severity and the duration of illness.