There is a lack of valid epidemiological data on malignancy-associated pain in modern pediatric oncology. Pediatric oncology patients (self-assessment) and their parents from 28 hospitals were questioned using age-adapted, structured interviews and validated pain assessment tools. Pain intensity was measured by the NRS and Bieri faces scale. We conducted 363 interviews with patients and their parents, and 46 with the parents alone (if patients <2.5 years). Pain was reported at the time of the interview or within the last 24 h, 7 d, or 4 weeks in 15%, 28%, 50% and 58% of cases, respectively. The proportion of patients suffering severe to maximal pain (NRS>3; Bieri>2) increased significantly (p=0.001, chi2 test). The median pain intensity for the most severe pain episode within the last 4 weeks was 6.7 (NRS 0-10). Adverse effects of anti-tumor therapy were the most frequent cause of pain. Multivariate analyses depicted general physical condition either "severely reduced" (ASA status 3) (OR 4.0, 95% CI 1.1-14.7, p=0.037) or "moderately reduced" (ASA status 2) (OR 1.8, 95% CI 1.1-2.9, p=0.018), "in-patient status" (OR 1.8, 95% CI 1.2-2.9, p=0.010), and "co-morbidity present" (OR 3.5, 95% CI 1.1-10.7, p=0.030) as risk factors for severe to maximal pain. General anesthesia was the only factor significantly (OR 0.14, 95% CI 0.05-0.39, p<0.01) associated with a reduction in the proportion of patients suffering severe to maximal pain during bone marrow aspiration. Our data emphasize both the importance of in-house acute pain control and the need for general anesthesia during painful procedures in pediatric oncology.