The primary goal of this proposal is to initiate a collaborative full- scale trial to test whether medical therapy (finasteride and/or doxazosin) delays or prevents the progression of symptoms of BPH or if it relieves these symptoms, and the duration of these effects. The primary outcome will be the time-to-progression of BPH. Clinical progression is defined as the occurrence of one or more of the following: acute urinary retention, renal insufficiency due to BPH, recurrent urinary tract infection, incontinence or an increase in AUA Symptom Score of 4 or more points. Approximately 2,800 study participants will be required for the full-scale trial, with 200 study participants randomized at UT Southwestern. A variety of secondary research questions will be addressed, including the value of diagnostic tests in predicting the progression of BPH and response to therapy, as well as a variety of tissue-based analyses yet to be defined. The Division of Urology at UT Southwestern served as one of the pilot Centers in the NIH/BPH Study, recruiting the requested number of patients and meeting all protocol and data entry requirements. We have an extensive experience with BPH clinical trial design and conduct. Our recruitment strategies to randomize 200 patients over two years are outlined. In addition, our group has an active basic prostate research program and hope to actively participate in the design of biochemical/molecular studies to be performed on the prostate tissue biopsies.