Parenting Stress in Mothers of Children with Down Syndrome in Preschool Age Research suggests that parenting stress is elevated in parents of children with intellectual disabilities. However, data are inconsistent if this holds true for parents of children with Down syndrome. As part of the Heidelberg Down syndrome study, 52 mothers of children with Down syndrome (mean age: 5 years) completed the German adaptation of the Parenting Stress Index. These results show significantly elevated stress scores in scales measuring demanding and less acceptable behavior of the children (child characteristics). Scores in scales measuring parent characteristics do not differ significantly from the norms. Global stress scores are associated with the degree of behavioral problems (SDQ) and adaptive competence (VABS-II). A regression analysis points to optimism as a dispositional trait of the mother which makes a significant contribution to the prediction of parenting stress scores. The implications for early intervention are discussed.