Fifty-five consecutive patients with recurrent intracranial malignant gliomas were reoperated at Memorial Sloan-Kettering Cancer Center from 1972 to 1983. The patients were 10 to 70 years old (median, 48 years). Thirty-five patients (64%) had glioblastoma multiforme, and 20 (36%) had anaplastic astrocytoma. The median interval between the first operation and reoperation was 43 weeks. The Karnofsky rating before reoperation ranged from 40 to 90 (median, 70). Eleven patients (20%) had more than one reoperation. The mortality rate was 1.4% per procedure, and the morbidity rate was 16% per procedure. After reoperation, 41 patients (75%) had chemotherapy and/or radiation therapy. The median survival for all patients was 92 weeks. The median survival after reoperation was 36 weeks. Patients with Karnofsky ratings of greater than or equal to 70, with anaplastic astrocytomas, or in whom gross total removal of the tumor was undertaken lived longer than their respective counterparts (P less than 0.05). Prereoperation Karnofsky rating and extent of surgical resection were the most important independent factors related to survival after reoperation according to multivariate analysis (P less than 0.01 and P less than 0.05, respectively). Twenty-five patients (45%) had improved Karnofsky ratings after reoperation, and the 32 patients (58%) who were independent after reoperation were able to stay so for more than 6 months of their survival time (median value). Reoperation is feasible and can be accomplished with acceptable mortality and morbidity. When intracranial malignant gliomas recur, the combined use of reoperation and adjuvant therapy prolongs good quality life.(ABSTRACT TRUNCATED AT 250 WORDS)