Aging is associated with loss of tissue mass and a decline in adult stem cell function in many tissues. In contrast, aging in the prostate is associated with growth-related diseases including benign prostatic hyperplasia (BPH). Surprisingly, the effects of aging on prostate epithelial cells have not been established. Here we find that organoid-forming progenitor activity of mouse prostate basal and luminal cells is maintained with age. This is caused by an age-related expansion of progenitor-like luminal cells that share features with human prostate luminal progenitor cells. The increase in luminal progenitor cells may contribute to greater risk for growth-related disease in the aging prostate. Importantly, we demonstrate expansion of human luminal progenitor cells in BPH. In summary, we define a Trop2⁺ luminal progenitor subset and identify an age-related shift in the luminal compartment of the mouse and human prostate epithelium.