AbstractChromosome studies of a malignant lymphoma of the brain were made by G-, Q-, and C-banding techniques and by autoradiography. The tumor had a modal chromosome number of 47 and contained 4 markers: 1q−, 6p+, 11q+, and 14q+. A 14q+ marker chromosome frequently seen in malignant lymphomas was identified as a translocation between chromosomes #1 and 14 in this case. Although the banding pattern did not reveal abnormalities in chromosomes #22, the late replication of one chromosome #22 was detected by autoradiography. The abnormality of chromosomes #14 and 22 was discussed in relation to its occurrence in brain tumors, and the application of autoradiography in addition to banding techniques was stressed as necessary in cytogenetic studies of tumor chromosomes.