Familial neuroblastoma is of special interest in view of the oncogenesis of this tumour with its early manifestation in childhood. The inheritance seems to follow an autosomal-dominant mendelian trait with incomplete penetrance. Familial neuroblastomas and ganglioneuromas have not been reported in detail within large treatment studies. A retrospective clinicopathological survey of patients reported to the German neuroblastoma treatment studies over 24 years was performed. Among 2863 patients (2752 neuroblastomas, 111 ganglioneuromas) included in five consecutive trials, only 22 hereditary cases in ten families were observed. Neuroblastomas were found in 18 patients and ganglioneuromas in four, accounting for less than one percent of all cases. Six patients with neuroblastomas had localised disease, seven had stage 4, three had stage 4S, and stage was unknown in two patients. Two families had three affected patients. Contrary to previous reports, age distribution and number of primary tumours in patients with familial data confirm the low prevalence of familial neuroblastoma and may help in counselling the affected families.