Seven patients from a series of 400 parasellar lesions presenting with visual failure treated in the Gough-Cooper Department of Neurological Surgery, The National Hospital for Nervous Diseases, Queen Square, were found to have low-grade gliomas of the hypothalamus. All were retrochiasmatic in site. The median age was 18 years. All showed low-grade astrocytoma, grade 2 and, in 6 of the 7 cases, presentation was with a variety of visual problems including homonymous hemianopia, bitemporal hemianopia, and unilateral scotomata. The other case presented with papilledema. Skull x-rays were, by and large, normal. Computed tomography scanning showed low- or mixed-density midline lesions and angiography showed mass effect and occasionally a capsular blush. All were operated on directly through a variety of approaches, and in each case, a radical subtotal removal was carried out. Postoperatively there were no major complications and no major worsening of symptoms in any patient. Radiotherapy was applied in 6 of the 7 cases. Follow-up periods range from 6 months to 6 years and 5 of the 7 patients remain well. The other 2, who are surviving, have advancing neurological disturbance.