Introduction. Evidence shows that sexual dysfunctions (SDs) are very prevalent in both sexes and that they share risk factors with many other conditions. It is known that only a minority of people experiencing sexual problems seek treatment, but the role of the general practitioner (GP) in SD diagnosis and treatment is relatively unexplored. No study has been conducted in Portugal in order to identify GPs' knowledge, attitudes, beliefs, and practices regarding SD and only a small amount of similar studies from other countries have been published. Aim. To characterize GPs' knowledge, attitudes, and beliefs concerning SD; practices of SD management in daily practice; self-perceived competence in discussing and treating SD; and need for training. Methods. Cross-sectional study using confidential self-administered questionnaires applied to GPs working in Primary Health Care Units in the Lisbon region. Main Outcome Measures. The questionnaire collected information concerning GPs' knowledge and perceptions regarding SD, training and practice in sexual health, criteria for initiating discussion and treatment, and the adoption of guidelines. Results. A total of 50 questionnaires (30 females) were obtained (73.5% response rate). On average, the 50 participants were 52 +/- 8.6 years old, had 21 +/- 8.2 years of family practice, and followed 1,613 +/- 364 patients. The degree in medicine was never considered as an extremely adequate source of information both for male and female SD. Lack of time to obtain relevant information for clinical practice and to deal with sexual health issues were perceived as important barriers in initiating a discussion with the patient, as well as lack of academic training and experience in this area. Conclusions. GPs expressed a high need for continuous training in this area and more than half considered that their degree was not an adequate source of training. These results indicate that there is a need for both pregraduate and postgraduate training in this area. Alarcao V, Ribeiro S, Miranda FL, Carreira M, Dias T, Garcia e Costa J, and Galvao-Teles A. General practitioners' knowledge, attitudes, beliefs, and practices in the management of sexual dysfunctionResults of the Portuguese SEXOS Study. J Sex Med.