Peutz-Jeghers syndrome (PSJ) is a relatively rare but well-recognized condition, with a prevalence of approximately one in 120,000 births in the USA. It is generally inherited as an autosomal dominant trait, although 35% of cases are new mutations. This disorder is characterized by melanocytic macules on the hands, feet, peri-oral skin and oral mucosa, and multiple gastrointestinal hamartomatous polyps. People with PSJ have an increased risk for developing a variety of malignant tumours. The aim of the present study was to report one case of PSJ in a 14-year-old boy with mucocutaneous pigmentation associated with duodenal hamartomatous polyps.