Objective To assess the role of telomerase activity as a marker for the development of prostate cancer in men with existing benign prostatic hyperplasia (BPH), a known risk factor for prostatic carcinoma. Materials and methods Telomerase activity was assayed, using a highly sensitive polymerase‐chain reaction‐based assay, in nine biopsies from patients with prostatic cancer, 16 from patients clinically diagnosed with BPH and 11 from patients with no evidence of prostatic disease. Results Telomerase activity was detectable in eight of the nine prostate cancer biopsies, in none of the normal prostates and in six of the 16 BPH biopsies. Conclusion The finding of telomerase activity in six of 16 biopsies from patients with BPH could indicate early prostate cancer and suggests that telomerase activity may be of use as a biomarker in patients diagnosed with BPH and who may subsequently develop prostate cancer.