The epidemiology of benign prostatic hyperplasia (BPH) and male lower urinary tract symptoms (LUTS) has evolved considerably during the past several years. The term LUTS describes a distinct phenotype and allows for a broad epidemiologic description of urinary symptoms at a population level. Although it is becoming the preferred term for studying urinary symptoms in populations, LUTS remains interconnected with BPH in the literature. The incidence and prevalence of BPH and LUTS are increasing rapidly as the US population ages. BPH and LUTS are associated with serious medical morbidities, an increased risk of falls, depression, diminished health-related quality of life, and billions of dollars in annual health care costs. Although age and genetics play important roles in the etiology of BPH and LUTS, recent insights at the population level have revealed that modifiable risk factors are likely key components as well. Serum dihydrotestosterone, obesity, elevated fasting glucose, diabetes, fat and red meat intake, and inflammation increase the risk; vegetables, regular alcohol consumption, exercise, and NSAIDs decrease the risk.