An observation of Peutz-Jeghers syndrome, in a 13 year old girl, provides the Authors with the opportunity of reviewing the clinical features, the natural history and the complications of the disease, mainly the malignancies. In recent reviews the occurrence of cancer was further on investigated: gastrointestinal and non gastrointestinal tumors occurred in 22-48% of the patients examined. The surveillance protocols of the subjects at risk and genetic counseling are discussed.