Five prospective, multicentre adult renal studies of three yr duration conducted in Europe for which tacrolimus was used as the primary immunosuppressant in at least one treatment arm was identified. This was confirmed by literature review as the only source fulfilling these criteria. Our goal was to identify absolute (reported) incidences of malignancies in patients exposed to tacrolimus and relative rates as a proportion of the total malignancies recorded for three yr after transplant. The five studies provided 2435 patients in nine different treatment regimens. All regimens combined tacrolimus with azathioprine or mycophenolate mofetil and corticosteroids except for one regimen which also employed daclizumab without corticosteroids. There were 83 patients with malignancies or 3.4% of the total population. No patient experienced more than I malignancy type. Malignancy incidences relative to those patients experiencing a malignancy were: total skin 37.3%, lymphoma 15.7%, and non-skin-non-lymphoma 47.0%. Annual occurrence of all malignancies reflected a progressive increase with time. While the larger proportion of lymphoma and non-skin-non-lymphoma malignancies occurred during the first year after transplant, malignancies affecting the skin increased more linearly with time. These findings are consistent with reports in the literature, reflect the current established experience with tacrolimus to date, and should provide a robust basis for future comparisons with tacrolimus-based immunosuppression.