The morphology and functional changes of thymus, spleen and T lymphocytes were studied in vasectomized rabbits. The results showed that: (1) A significant low weight of thymus and spleen, and a slight or medium atrophy of thymic lobules and shrinked splenic nodules and lymphoid tissues were observed in the rabbits vasectomized for 6 months (VG6 rabbits). (2) Spontaneous-proliferation of thymus could not be affected by vasectomy. (3) The lowest activity of IL-2 was detected in the supernatant of spleen cell culture of VG6 rabbits. The morphology and functional changes of thymus, spleen and T lymphocytes were studied in vasectomized rabbits. The results showed that: (1) A significant low weight of thymus and spleen, and a slight or medium atrophy of thymic lobules and shrinked splenic nodules and lymphoid tissues were observed in the rabbits vasectomized for 6 months (VG6 rabbits). (2) Spontaneous-proliferation of thymus could not be affected by vasectomy. (3) The lowest activity of IL-2 was detected in the supernatant of spleen cell culture of VG6 rabbits.