Computed tomographic (CT) or angiographic (or both) findings were analyzed in 32 cases of pathologically proved primary non-Hodgkin lymphoma of the central nervous system. CT scans were available in 28 of the 32 cases. Thirty lesions were found in the 28 cases. In comparison with previous literature, the frequency of involvement of deep central structures (30%), multiple lesions (11%), and subependymal lesions (4%) was lower and that of lesions in the periphery of the supratentorial compartment was higher (46%). In agreement with previous literature, most of the lesions were of increased density (63%), enhanced (100%), and enhanced homogeneously (71%). Twenty-nine of the 32 patients underwent cerebral angiography. In 12 patients, a homogeneous vascular stain was found that appeared in the late arterial or early venous phase and had a meningiomalike pattern. This staining pattern has not been emphasized sufficiently in previous literature. It was believed that such an angiographic pattern in a dense, homogeneously enhancing parenchymal lesion is suggestive of a primary lymphoma of the central nervous system. Magnetic resonance imaging was performed in one patient with two lesions, and both lesions demonstrated prolonged T2 relaxation times.