The disease entity of benign prostatic hyperplasia (BPH) is characterized by the interaction of anatomical hyperplasia of the prostate, urodynamic subvesical obstruction, the response of the detrusor muscle, and the subjective symptom complex of prostatism. A comprehensive evaluation of a patient presenting with symptoms suggestive of this disease should include an assessment of each of these conditions. Similarly, treatments for BPH should be judged by their ability to influence all these conditions or selected ones. The administration of a standardized symptom score, a digital rectal examination, and a urodynamic evaluation tailored to the specific situation of each patient constitute a set of subjective and objective response criteria for the diagnosis of BPH and the evaluation of treatment response.