It is generally established that telomerase activity is present in most cancer cells, germ line cells, and established cell lines but typically is not present in normal somatic cells. Among the few exceptions, telomerase activity has been detected in hematopoietic stem cells and in physiologically renewable epithelial cell populations (e.g. skin, small intestine). The adult rat prostate gland is a tissue that has the ability to regenerate in response to androgen. We hypothesized, therefore, that telomerase activity should be present in the normal adult rat prostate. In this study, using a highly sensitive PCR-based telomerase assay [the telomerase repeat amplification protocol (TRAP) assay], we tested this hypothesis by measuring telomerase activity in the ventral, dorsal, lateral, and anterior lobes of the adult rat prostate. We show herein that telomerase activity indeed is present in whole tissue extracts of the ventral, dorsal, and anterior lobes, though at differing levels, but not the lateral lobe. However, lateral lobe prostatic fluid was found to contain one or more factors inhibitory for the TRAP reaction, and therefore, telomerase activity was detected after removal of this fluid. Telomerase activities were not uniform within the prostatic ducts, but rather telomerase positive cells are regionally distributed within the distal, intermediate, and proximal ducts of the microdissected segments of each of the lobes. We speculate from these results that androgen-stimulated regeneration of rat prostate following androgen ablation may depend upon the telomerase-positive regenerating pool of cells present within specific regions of the ductal network.