No detailed data exist on an association between combined cyclosporin (CsA) and dihydropyridine (DHP) medication and gingival overgrowth among renal patients. Thirty-five renal transplant recipients treated with CsA and 28 uraemic patients participated in this research. Fourteen of the recipients and 14 of the uraemic patients were receiving DHP. The examination included determination of the duration of the CsA and DHP treatment protocols, the mean daily oral dose of DHP, and periodontal status. Gingival overgrowth was classified into four categories according to the clinical changes: score 0 = no gingival overgrowth, score 1 = mild gingival overgrowth, score 2 = moderate gingival overgrowth, and score 3 = severe gingival overgrowth. The prevalence of clinically obvious gingival overgrowth (scores 2 and 3) was 35% in those treated with CsA and DHP, 24% with CsA and 21% with DHP. The concomitant administration of CsA and DHP resulted in a significantly increased percentage of scores 2 and 3 overgrown gingival units as compared with DHP alone (P < 0.05). Gingival overgrowth (scores 1, 2, 3) did not correlate with either the daily oral dose of DHP or the duration of DHP treatment. Combined treatment with CsA and DHP did not significantly increase the prevalence of gingival overgrowth, but it did increase the severity of it among susceptible patients.