94 children with a primary liver neoplasm were registered in the Cooperative Pediatric Liver Tumor Study HB-89 of the GPOH from 1988 to 1992. 64 of these had a hepatoblastoma (HB), 12 a hepatocellular carcinoma (HCC), 2 a sarcoma and 16 a benign tumor. 51 (80%) patients with an HB were 6 to 36 months of age, 9 with an HCC above 10 years. Initial serum-alpha-fetoprotein (AFP) was elevated in 51 HB patients and exceeded the 3-fold of normal range in 45. Children with low (< 100 ng/ml) and very high (> 1,000,000 ng/ml) levels had a significantly worse prognosis than those with intermediate values (p = 0.0014). AFP was moderately elevated in 9 HCC patients. All other tumor markers were only irregularly above normal range. 48 (77%) of HB patients survived, 45 (73%) are tumor free. All of 18 stage I and 4/5 stage II patients are in remission. After chemotherapy 30/36 stage III HBs and 2/5 stage IV HBs could be resected, 9 of these patients suffered from tumor relapse. Disease-free survival was 100% for stage I, 80% for stage II, 68% for stage III and zero for stage IV HB (p = 0.0005). Surgical complications occurred after 8% of biopsies, 13% of limited primary resections and 25% of extended secondary resections. There was no perioperative death. The completeness of tumor resection at primary or delayed surgery correlated significantly with patients disease-free survival (p < 0.0001). Chemotherapy with ifosfamide, cisplatin and adriamycin was effective in HB. 203 courses were given in 61 patients.(ABSTRACT TRUNCATED AT 250 WORDS)