Twenty-one familial Mediterranean fever (FMF) patients who received a kidney transplant for terminal renal failure due to amyloidosis were studied retrospectively to evaluate the prophylactic effect of colchicine on graft amyloidosis. Proteinuria, highly suggestive of kidney transplant amyloidosis, developed in 11 patients within a median of 3 years after transplantation (range 0.5-10 years). In 10 patients, repeated urinalyses for protein were negative during a median of 5 years after transplantation (range 1-13). Patients who developed proteinuria or transplant amyloidosis received smaller colchicine doses than patients without proteinuria--mean 0.69 (range 0-1) versus 1.53 (range 1-2) milligrams per day (p = 0.0002), suggesting that colchicine prevents or delays development of transplant amyloidosis. This prophylactic effect of colchicine was complete at a dose of 1.5 mg/day or more and absent at a daily dose of 0.5 mg or less. In patients who received 1 mg/day, individual variability in the response to colchicine was observed. We conclude that the development of amyloidosis of the kidney transplant in FMF is inevitable at a colchicine dose lower than 1 mg/day, unpredictable at 1 mg/day and usually preventable with 1.5 mg/day or more.