We investigated whether a positive intervention (i.e. granting a wish) in children with a chronic illness could promote positive psychological responses in their parents. Hospitalized children were randomly assigned to either the wish group or to a waiting-list control group. Mothers and fathers’ responses (N = 86 and 38, respectively) were studied. Parents from the wish group showed higher levels of positive emotions and beliefs in a benevolent world than the control group. Mothers from the wish group reported higher benefit finding, gratitude, and love than those in the control group. Given that the child’s illness inevitably affects their parents, it is important to promote studies that include parents’ well-being dimensions.