Disagreement exists concerning the natural history and treatment of chiasmatic gliomas (CG) of childhood. We reviewed our experience in 21 cases of surgically verified CG with a median age of 4 years at time of diagnosis, followed for a median of 5.3 years (range 3-14.8 years). Initial treatment included radiation therapy (RT) in 18 patients, chemotherapy in 2, and observation in 1. Disease recurrence, defined as progressive visual or neurological deterioration, was documented in 10 children (48%), occurring at a median of 6 years after diagnosis. 5-year actuarial survival was 89%, but fell to 60% by 10 years. Visual improvement after RT was uncommon, occurring once. Intellectual deficits were noted in 5 of 17 survivors. We compared our results to that of other patients reported and concluded that: (1) CG may act aggressively independent of their location in the visual pathway at time of diagnosis; (2) the beneficial effects of RT are difficult to document; (3) progressive disease may occur late in the course of illness, and (4) intellectual sequelae are common in long-term survivors.