This chapter, written for undergraduate medical students and post-graduate doctors in training, presents information on how to manage insomnia — a case which they are likely to encounter in the future in a general practice setting. It presents the case of a 28-year-old man who has a 6-month history of insomnia. He has a problem falling asleep; sometimes wakes again at about 4:30 am and then later has to force himself to wake and get out of bed at 6:30 am to prepare to go to work. 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.