Premature ejaculation (PE) is likely the most common sexual dysfunction in men, with a worldwide prevalence of approximately 30%. To date, the lack of a universally acknowledged definition of PE has complicated the examination and analysis of PE in clinical and research-related settings. The impact of PE on men and their partners also needs to be clearly defined. Clearly, a better understanding of the epidemiology of this disorder, especially with regard to prevalence and risk factors, is necessary. The prevalence of PE appears to vary across socio-cultural and geographic populations. The elucidation of the etiology of PE and risk factors associated with PE has been difficult. However, several risk factors for PE exist that have strong support in the literature. Clearly, an improved and universal definition and understanding of PE and its epidemiology will improve the clinical management of PE and the success of future epidemiologic studies and clinical trials.