Nocturia is currently defined as the complaint that an individual has to wake at night > or =1 times to void. Nocturia is a highly prevalent and bothersome condition, associated with serious medical conditions, as well as increased mortality risk. However, it remains an underreported, underdiagnosed, and undertreated condition, with many patients accepting it as a natural consequence of aging. Therefore nocturia as a condition deserves public health attention. Nocturia is a multifactorial condition that can coexist with other lower urinary tract symptoms, and the most common causal factor is nighttime overproduction of urine. Recent studies have improved our understanding of nocturia while introducing a growing number of therapeutic options. This paper aims to review the classification, etiology, evaluation and treatment of nocturia to help healthcare providers better serve patients who have nocturia.