The present study examined trait perfectionism, automatic perfectionistic thoughts, rumination, worry, and depressive symptoms in early adolescents. A group of 81 elementary school students in Grades 7 and 8 completed 5 questionnaires: the Child-Adolescent Perfectionism Scale, the Perfectionism Cognitions Inventory, the Children's Response Styles Questionnaire, the Penn State Worry Questionnaire for Children, and the Center for Epidemiologic Studies Depression Scale. The correlational results revealed associations between both trait perfectionism and perfectionistic automatic thoughts and the indices of depression and worry. Rumination was associated with perfectionistic automatic thoughts, self-oriented perfectionism, depression, and worry. Tests of mediation indicated that rumination mediated the association between perfectionism and depressive symptoms, thus highlighting the role of maladaptive forms of cognitive reactivity in perfectionism. The findings suggested that perfectionistic children and youth are at-risk due to cognitive vulnerabilities and they should benefit from programs focused jointly on reducing perfectionism, associated cognitive tendencies, and susceptibility to depression and worry. (Contains 3 tables.)