Data concerning a study on lymphoid infiltration in 61 cerebral malignant gliomas are reported. Lymphoid cellular infiltrates were found in 28 cases (45.9%): 8 (13.1%) with marked and 20 (32.8%) with slight infiltration; the remaining 33 cases (54.1%) did not exhibit lymphoid infiltration. The mean survival time (+/- standard deviation) of patients harboring gliomas with marked lymphoid infiltration was 20.5 (+/-19.9) months, and that of patients with slight lymphoid infiltration in their glioma was 10.3 (+/- 7.5) months; those patients having gliomas without lymphoid cellular infiltrates showed a mean survival time (+/- standard deviation) of 7.2 (+/-6.1) months.