Cyclosporin A (CsA) is used widely as an immunosuppressive in organ transplantation. Although it is highly effective, acute and chronic nephrotoxicity of CsA are of continuing concern. A case of acute glomerular thrombosis secondary to CsA therapy in a renal transplant recipient is described. The course of the accompanying acute renal failure and its reversal following discontinuation of CsA and therapy with intra-arterial streptokinase is outlined. CsA-induced capillary thrombosis is rare but has been described in renal transplant recipients as well as in hepatic and bone marrow transplantation. It may give rise to diagnostic confusion in the early days following renal transplantation, where it may mimic acute rejection. The etiology of CsA-induced glomerular capillary thrombosis remains speculative.