Objective: Little is known about telomere dynamics in keloids. As keloid formation is dependent on cell replication, in theory telomeres should be shorter in keloids than in normal skin. We examined this concept in the present study. Methods: We measured by Southern blot analysis telomere length in keloids and in adjacent normal skin of 16 individuals. When available, we also measured telomere length in blood (leukocytes) and subcutaneous fat. Results: Telomere length was highly variable among individuals but highly correlated among tissues (cells) within the individual. The mean telomere length in the keloids was longer than that in the adjacent normal skin and displayed a length gradient, with the mean length of telomeres shorter just below the epidermis and longer at the base of the keloids. No apparent telomerase activity was detected in the keloids. Conclusions: Our findings suggest a transient activation of telomerase, the reverse transcriptase that prevents telomere shortening, probably during the early phase of keloid formation. The activation of telomerase serves to maintain (or even elongate) telomere length in the keloid. However, telomerase activity is repressed in the fully developed keloid.