Peutz-Jeghers syndrome is a rare, autosomal dominant inherited disorder, which is characterized by mucocutaneous pigmentations, gastrointestinal polyposis and an increased risk of cancer. It is caused by germline mutations in the LKB1 tumour suppressor gene, as a result of which hamartomatous polyps can develop already at an early age, which may cause various complications, including abdominal pain, anaemia, and acute intestinal obstruction. Patients have an increased risk of developing cancer, in the gastroinstestinal tract and in other organs. As a result of the risk of complications related to the hamartomatous polyps and the increased risk of cancer, the medical management mainly consists of surveillance. Upper and lower endoscopies are recommended for surveillance, the small bowel should be investigated with magnetic resonance imaging and regular inspection of the pancreas with imaging techniques is recommended. Women are advised to seek regular breast- and gynaecological screening from an early age. The pathogenesis of hamartomas and carcinomas is unclear. More insight into the molecular background might lead to targeted medicinal therapies for patients with this syndrome.