This study examined the psychometric properties of four new health belief measures for asthmatic children and their parents. A total of 110 asthmatic children (aged 7-15) and 129 parents (with asthmatic children aged 3-15) responded to a mail-out survey. Evidence for reliability (0.75-0.87) and validity was obtained for measures of Parent Barriers to Managing Asthma, Parent Asthma Self-Efficacy (subscales: attack prevention and attack management), Parent Treatment Efficacy, and Child Asthma Self-Efficacy (subscales: attack prevention and attack management). All measures were correlated in the hypothesized directions with health status, asthma symptoms, and impact of illness on the family.