The authors review the therapeutic results of 20 patients (aged 12 months to 30 years, mean age 9 years) with benign pilocytic astrocytoma of the chiasmatic/hypothalamic region, seen at the University Hospital Hamburg-Eppendorf between February 1980 and April 1993. Six patients suffered from neurofibromatosis 1 (NF-1). The patients were divided into two subgroups relative to tumour extension and growth patterns, as revealed by CT scans and/or MR imaging. Fourteen patients revealed a large globular suprasellar tumour extending into the hypothalamus and/or the anterior third ventricle (group A). A suprasellar tumour with optic tract involvement could be identified in six cases (group B). Subtotal (70-90%) resection was achieved in ten tumours (50%), the majority of which were of the large globular type. There were no deaths. Postoperative morbidity was comprised of visual and endocrine impairment in four patients and right hemiparesis and dysphasia in one patient. Radiation therapy was given in nine cases (45%). Three tumours (38%) were reduced in size by irradiation. Tumour progression was seen in seven patients (35%). The presence of young age and NF-1 were predictors of progressive disease in our series. Growth capacity was not related to the extent of cytoreductive surgery.