This study aimed to evaluate prevalence and risk factors for emotional and behavioral problems in dependent children of cancer patients using a multinational research design. The sample comprised 350 ill parents, 250 healthy partners, and 352 children. Parents assessed the child's psychological functioning using the Child Behavior Checklist, parental depression using the Beck Depression Inventory, family functioning using the General Functioning subscale of the Family Assessment Device, quality of life using short-form questionnaire, and adolescents (N = 168) self-reported psychological functioning using the Youth Self Report. Children and adolescents, in particular latency-aged boys and adolescent girls, were of higher risk of psychosocial problems than norms. There was a higher risk of problems when the father was ill than when the mother was ill, but it remains unclear whether this difference was due to the different diagnoses of fathers and mothers, gender or other factors. The best predictor of internalizing problems in children and adolescents was parental depression, and the best predictor of externalizing problems in children and adolescents was family dysfunction. The results indicate the need for a family-oriented approach to psychological support of cancer patients.