The purpose of this study was to address the question of why, when there is a comparable severity of asthma, medical facilities, and treatments, some children develop controlled asthma whereas other children do not and are frequently ill. The major research questions pertained to whether families with a child with uncontrolled asthma differ from families with a child with controlled asthma as regards family characteristics and child-rearing attitudes, whether particular psychosocial variables relate to the severity of the asthma, and whether the interaction between the severity of the asthma and its controllability may clarify the role of psychosocial variables. Two studies were conducted, in which 70 asthmatic children (age range 9-15 years) and their families participated. The children and their caregivers were presented with measures assessing parental child-rearing attitudes, the problem-solving abilities of the caregivers, family functioning, and emotional disorders in the asthmatic children. Contrary to the assumptions derived from the psychosomatic family model, the findings of these studies suggest, among other things, that cohesion of family members and rigid manner of function of caregivers may have a positive rather than a negative influence on the welfare of the asthmatic child. In addition, controlled asthma was found to relate to the correct use of medication, which was predominantly evident in more structured and interdependent family environments. Of major importance is the conclusion that a distinction between controlled and uncontrolled asthma leads to a better insight into the role of psychosomatic variables than a distinction on the basis of the severity of the asthma.