To define optimum treatment and delineate recurrence patterns and prognostic factors in oligodendrogliomas, the authors reviewed the records of 49 patients who received treatment for these rare tumors between 1957 and 1990; 41 patients had at least 5 years follow-up. Age, race, gender, performance of computed tomography (CT), tumor location and grade, histologic findings, calcifications, surgery with or without postoperative radiation therapy, and the doses and fields used in radiation therapy were evaluate for prognostic relevance by means of chi 2 and Wilcoxon log-rank tests. Metaanalysis of relevant literature was also performed. Actuarial survival at 5, 10, and 15 years was 61%, 41%, and 24%, respectively. The pattern of recurrence was predominantly local alone (30 of 31 patients [97%] with recurrence). Age younger than 40 years, low-grade tumor, calcifications, and performance of CT were statistically significant prognostic factors. A trend existed toward improved 5-year survival in patients who underwent postoperative radiation therapy (P = .067); at stratification for subtotal resection, this improvement became significant (74% vs 25%, P = .019). Metaanalysis demonstrated a survival advantage for surgery with radiation therapy versus surgery only (56% vs 42%, P < .01).