The recent observation of a new HNPCC patient case induced the Authors to review their experience with the syndrome as well as to make an up to date of the problems related to diagnosis, surgical management, surveillance and genetic counselling for such patients with a lifelong high cancer risk. Patients with HNPCC and their first-degree relatives, whose risk of early colorectal carcinoma (especially in the proximal colon) as well as a variety of extracolonic cancers (particularly endometrium, ovary, stomach, small bowel, ureter and renal pelvis) is significantly higher then that of patients with sporadic carcinoma, should be properly managed with surgery and then with endoscopic examination (ideally all life long) starting--in unaffected individuals--at early age (25 years old). Problems related to genetic counselling are considered as well.