The activity of systemic lupus erythematosus (SLE) was investigated in 18 recipients of 20 renal transplants by retrospective analysis of their medical records and by screening the ten patients with more than one year follow-up. Eight grafts were lost, all because of rejection occurring within the first year. From the 12 patients with functioning transplants, one was lost to follow-up at seven years and another had not completed one year. The remaining ten patients were studied, and no evidence of lupus nephritis was found despite serologically active SLE in four cases. Their follow-up was 4.5 +/- 1.3 years. Our study provides the relatively scarce literature on renal transplantation in patients with SLE with a series of 18 recipients of 20 allografts, confirms that the recurrence of lupus nephritis in the allografts is very rare, as previously suggested, and discloses that graft and patient survivals are comparable with those of the general nondiabetic transplant population.