Between January and December 1985, 17 children with advanced neuroblastoma who were greater than 1 year old (16 stage IV, one stage III) were administered cisplatin (CPDD, 200 mg/m2) and etoposide (VP-16, 500 mg/m2) as a pilot study of toxicity and response rates for the European Neuroblastoma Study Group (ENSG). The study was designed to assess toxicity of two courses of treatment, and evaluate response rates after this short therapy. The creatinine clearance declined in seven of 15 patients. No patient experienced clinically significant hearing loss, but formal audiometric assessment of nine children revealed characteristic high tone loss in seven patients. Peripheral neuropathy was not seen. Asymptomatic hypomagnesemia (less than 0.7 microEq/L) was frequent, despite routine supplementation. Asymptomatic electrolyte imbalances occurred frequently, but were generally transient. Myelosuppression was severe, but brief. Seven patients required platelet transfusions and seven were readmitted between courses due to febrile episodes while neutropenic. There were no treatment-related deaths. According to strictly defined criteria, 12 of 17 patients showed a partial response (PR), and extensive marrow evaluation showed complete clearing of disease in six of 15 patients. This high-dose regimen, if carefully supervised, is associated with acceptable toxicity, comparable to that seen when the dose of CPDD is spread over several months. The rapidity and degree of response was encouraging and merits further evaluation.