Benign prostatic hyperplasia (BPH) is a common histologic condition among older men, which conveys its morbidity through lower urinary tract symptoms and complications, such as acute urinary retention, obstructive uropathy, and urinary tract infections. The mechanisms linking the histologic process and lower urinary tract symptoms remain uncertain; prostatic enlargement and bladder outlet obstruction are involved. However, measurements of prostate size and the severity of bladder outlet obstruction correlate poorly with the severity of lower urinary tract symptoms. The severity of lower urinary tract symptoms associated with BPH can be measured reliably, from the patient’s perspective, with a number of validated questionnaires, including the International Prostate Symptom Score, the Danish Prostate Symptom Score, and the International Continence Society (ICS)male questionnaire. In the clinical setting, these questionnaires can be used (1) to assess the severity of symptoms in men with lower urinary tract symptoms that may be attributable to BPH, based on their age and clinical characteristics; and (2) to follow changes in symptoms over time and with treatment. None of these questionnaires can accurately determine whether a symptomatic patient has underlying bladder outlet obstruction. Additional questionnaires are available to measure the impact of lower urinary tract symptoms on men’s lives, as well as associated phenomena, such as continence and sexual function, which may be affected by BPH and its treatments. Men with a severe burden of lower urinary tract symptoms often have measurable decrements in overall health-related quality of life, which can be ameliorated by treatment.