The pretransplant evaluation of a patient with a rare diagnosis requires knowledge of the pathophysiology and the transplant literature. A 55-year-old man presented with hypertensive kidney failure and the clinical diagnosis of acute intermittent porphyria. Complications of acute intermittent porphyria, which is a defect of heme production, are due to the accumulation of heme intermediates often precipitated by medications. Based on animal data, cyclosporine is considered unsafe in patients with acute intermittent porphyria. As part of the pretransplant evaluation, the patient received separate trials of tacrolimus and cyclosporine, which did not stimulate his acute intermittent porphyria. Four months after a kidney transplant, the patient still had no signs of rejection or symptoms of acute intermittent porphyria. This is the first documented patient with acute intermittent porphyria who successfully received a kidney transplant using tacrolimus. Because of individual variations, pretransplant testing of calcineurin inhibitors should be continued in patients with acute intermittent porphyria.