The distribution of gingival overgrowth was investigated in a cohort of organ transplant patients, who were medicated with cyclosporin or the combination of cyclosporin and a calcium channel blocking drug. Gingival overgrowth scores were significantly higher at buccal sites than lingual-palatally (p < 0.0001). There was no significant difference between upper and lower overgrowth scores (p = 0.88). The most severe overgrowth was seen in the canine region. Overgrowth between the central incisors was significantly less than in the canine region (p > or = 0.044) and was similar to that in the molar and premolar region. Although raised overgrowth scores were associated with increased levels of plaque and gingival inflammation, the distribution could not be explained by this observation.