Mice with i.p. inoculated leukemia L1210 cells had lower total number of thymocytes, and reduced number of CD4+8+ thymocytes, but increased CD4+8- subpopulation. Adrenalectomy reduced the CD4-8+ subset of thymocytes. Leukemia in adrenalectomized animals induced similar changes in the number of thymocyte subpopulations as observed in normal animals. However, a decrease in CD4+8- thymocytes was noted and the animals had decreased number of CD4-8- cells as well. Splenocytes of CD4+8- subpopulation were more numerous in adrenalectomized animals. Leukemia induced increase in the number of CD4+8- and CD4-8+ splenocytes in both normal and adrenalectomized animals.