Although survival rates in childhood cancer have distinctly improved, pediatric cancer patients often experience various disease- and treatment-related side effects with long-term consequences. Despite current studies investigating inactivity and limitations in physical functioning and quality of life in pediatric cancer patients, only little information regarding specific deficits in physical functioning and quality of life has been available until now. No study has yet analyzed these parameters from a global perspective and then identified specific deficits in a mixed childhood cancer population. Within this cross-sectional pilot study, motor performance and quality of life of 26 pediatric cancer patients were assessed after inpatient medical treatment, using standardized motor test batteries (MOT 4-6; DMT 6-18) and a quality of life questionnaire (KINDL®). Reference data have been mainly provided by the German "Children and Young People Health Survey" (KiGGS). Patients achieved lower motor performance scores (p = .000) (more than 27% below the average of healthy peers). Specific deficits were identified in motor speed and motor control (4-6 years), as well as in endurance, strength and coordination under time pressure (6-17 years). In terms of quality of life, no significant differences were examined compared to healthy children of the same age. The results of this study confirm that children with oncological diseases frequently have specific motor problems. Future research in pediatric oncology must investigate the impact of targeted, individualized exercise interventions addressing these specific deficits.