According to the latest estimate of prevalence of sexual dysfunction in the United States, sexual dysfunction was reported by 31% of males in a national probability sample from the 1992 National Health and Social Life Survey. The prevalence of erectile dysfunction in that sample was 5%. Earlier estimates of male erectile dysfunction prevalence from community studies ranged from 3% to 9%. Rates of male erectile disorder among patients presenting for sex therapy were close to 40%. Primary and secondary male erectile disorder differ significantly in frequency (3.5%-8% vs. 48% - a difference of over 50%). The frequency of erectile failure generally increases with advancing age. In the report by Laumann et al., men ages 50-59 years had a threefold increase in the frequency of erectile dysfunction over that of men in younger age groups. Unfortunately, this study did not include men older than 59 years. Aging is a definite factor in all aspects of sexual functioning, as Schiavi (1999) has discussed in detail.

Various other factors - such as medical illness, pharmacological agents, psychopathology, stress, depression, deterioration in social status, and even history of sexually assaulting women - are associated with an increased prevalence of erectile dysfunction. The best-known medical condition is diabetes mellitus; prevalence estimates of male erectile disorder secondary to diabetes mellitus range from 27% to 71%. Spector and Carey noted that recent studies in clinical samples suggest an increase in the frequency of orgasmic and erectile dysfunctions.

Male erectile disorder is undoubtedly a common disorder, with an increased prevalence in both aging and in medically ill males. It is a frequent presenting complaint in sex clinics and urology offices. Nonetheless, the disorder remains underdiagnosed and undertreated.