From 1958 to 1982, 58 patients with craniopharyngioma were treated with external beam radiation, 56 post surgery. Nineteen were pediatric (< 16 years) and 39 were adult. Forty patients underwent primary treatment while 18 (7 pediatric and 11 adult) were treated for recurrence. Median follow-up is 17 years. Tumor dose and 'maximum dose' (i.e. dose to smallest isodose > 1 cm) were recorded. The mean tumor and maximum dose for pediatric patients was 5588 and 5870 cGy vs. 6243 and 6542 cGy, respectively for adults. The actuarial 5- and 10-year survivals for pediatric patients were 84% and 72%, respectively and were significantly better than the 54% and 51% for adults (p = 0.01). However, overall disease recurrence rates were 26% (5/19) for pediatric patients and 18% (7/39) for adults. Of the multiple patient and treatment parameters analyzed, initial disease type (i.e. primary vs. recurrence) in pediatric patients, surgical extent, tumor dose, maximum dose, age of adults and use of pretreatment CT evaluation appeared to impact on patient outcome. Pediatric patients treated for primary disease showed improved survival over those treated for recurrence. The same was not observed in adults and appeared to be due to treatment toxicity. Surgical morbidity correlated with extent of surgery. All patients who underwent total resection developed surgical sequelae. Forty-four percent (4/9) of patients receiving tumor doses of < or = 5400 cGy developed recurrences vs. 16% (8/49) in those receiving > 5400 cGy. Nine of the 12 recurrences were in patients who did not undergo pretreatment CT evaluation.(ABSTRACT TRUNCATED AT 250 WORDS)