The advisability of a second operation for recurrent glioblastoma multiforme or anaplastic astrocytoma depends on the expected duration and quality of subsequent survival. We reviewed the results in 70 consecutive patients who underwent reoperation for supratentorial glioblastoma multiforme (n = 39) or anaplastic astrocytoma (n = 31) between 1975 and 1984. The operative morbidity rate was 5.7% (4 of 70 patients); the 6-week postoperative mortality rate was 4.3% (3 of 70 patients). The median duration of survival after reoperation was 36 weeks in patients with glioblastoma multiforme and 88 weeks in those with anaplastic astrocytoma. The median duration of high quality survival (defined as the period during which the patient had a Karnofsky performance score of at least 70) after reoperation was 10 weeks for patients with glioblastoma multiforme and 83 weeks for patients with anaplastic astrocytoma. Age and preoperative Karnofsky score in patients with glioblastoma multiforme and age in patients with anaplastic astrocytoma had statistically significant effects on the duration of high quality survival after reoperation, but not on postoperative survival independent of quality. Although age and functional status do not significantly affect the duration of survival after reoperation, they do have a significant effect on the quality of life after reoperation. Frequently, a patient can expect to spend a greater portion of his life at a higher level of function than he would have without reoperation. As adjunctive forms of therapy improve, reoperation will play an increasingly prominent role in the management of recurrent malignant astrocytic tumors.