Sexual function in patients with Parkinson's disease has received virtually no attention. There are many reasons (physical, psychological and social), why such patients might experience problems within their sexual relationships. A group of patients and their partners completed a series of self-report measures, aimed at assessing sexual function and a range of factors which might be associated with any difficulties. The results revealed a high level of dysfunction, not just in the patients but also in their partners. Most effected were the couples in which the patient was male. A range of problems were reported by both patients and their partners. These were, in turn, associated with a range of variables relating to the disease, psychological and social factors. No simple causal model was suggested, and a multimodal therapeutic approach might be expected to have most benefit.