Posttraumatic growth (PTG) can occur after various types of trauma but has not been studied prospectively in parents of children with chronic diseases. In this study, PTG was assessed in 126 parents of 67 children with type 1 diabetes or cancer three years after diagnosis. Most parents (62.7%) reported at least a moderate degree of PTG. Quality of family relationships, parental psychological distress and child medical characteristics assessed one month after diagnosis, and parents' gender, explained 34 percent of PTG variance. The findings confirm that a severe disease of a child can lead to personal growth in the child's parents.