This chapter, written for undergraduate medical students and post-graduate doctors in training, presents information on how to manage erectile dysfunction — a case which they are likely to encounter in the future in a general practice setting. It presents the case of a 55-year-old fit and muscular landscape gardener who attends his surgery for review of the investigations for his erectile dysfunction. Over the last 2 years, he has noticed his erections becoming less strong and more recently he has experienced erectile failures that have become more common. The chapter provides details of the patients' medical history and the key findings of clinical examination, together with initial investigation results data for evaluation, and helps them develop their skills of clinical reasoning. Key questions then prompt the student to evaluate the patient, and reach a decision regarding their condition and the possible treatment plan.