The Kaposi's sarcoma, which was found in an immunosuppressed patient of renal transplantation, may have been developed by long term use of immunosuppressant agent after the renal transplantation. The case was a 29-year-old woman who was diagnosed as chronic renal failure in 1988, and since then, she had been on CAPD until May, 1997. After the renal transplantation in May 1997, the patient has been prescribed cyclosporin and prednisone as immunosuppressant agent. In June 1997, she showed clinical symptom of Kaposi's sarcoma with multiple papules and nodules in the skin and viscera, such as ureter, urinary bladder, stomach, duodenum and subcutaneous tissue of the chest. Multiple excisional biopsies were carried out in the skin, ureter, urinary bladder, stomach and duodenum. All of excisional biopses indicated nodular stages with extensive proliferation of spindle shaped, somewhat pleomorphic cells which have slit-like vascular spaces, proliferation of small vessels, and extravasation of erythrocytes. These lesions nearly diminished after sytemic chemotherpy, excision and discontinuity of immunosuppressive agents.