The incidence of impaired sexual function in adults with Parkinson's disease (PD) is greater than in the general population. Studies have examined different aspects of sexual function among adults with PD and their partners. Comparison groups have included healthy adults matched for age and gender, as well as age-matched controls with chronic, nonneurological disease with motor impairment. Impaired sexual function in PD is most likely multifactorial. Depression, physical disability, and autonomic dysfunction may contribute to the increased prevalence of erectile dysfunction (ED) among men with PD. Given this multifactorial basis, clinicians should routinely assess patient needs. For women with PD, therapeutic interventions and impaired sexual function have not been adequately described. Further research is required to develop treatment for adults with PD and sexual dysföunction.