Polyps refer to any mass projecting into the lumen throughout the gastrointestinal tract. They can be distinguished by their macroscopic appearance, but also by their histological structure. Disorders characterized by the presence of multiple polyps are called polyposis, and the most common polyposis syndrome is familial adenomatous polyposis (FAP). There are several variants of FAP associated conditions, all characterized by the appearance of hundreds to thousands of adenomas during the second decade of life and highly increased risk of cancer. FAP results from a germline mutation in the APC (adenomatous polyposis coli) tumor suppressor gene, or, in a minority of cases, from a mutation in MUTYH (mutY homolog) gene, so genetic testing can be used as a screening, for discriminating between affected and unaffected individuals. The diagnosis of FAP is confirmed by colonoscopic examination and, by the time, colectomy remains the only recommended treatment, although there are some studies showing positive effect of selective cyclooxygenase-2 inhibitors on reduction in the number and size of the adenomas. Between 2001 and 2013, 5 patients with familial adenomatous polyposis were diagnosed and followed up at the Department of Pediatrics, Clinical Hospital Center Zagreb. All the patients had positive family history, and three of them presented with rectal bleeding at the time of diagnosis. One patient was diagnosed as having carcinoma in situ. Due to high grade dysplasia of adenomatous polyps, all 5 patients underwent colectomy with no serious complications. In addition to intestinal polyps and associated conditions, there are numerous extraintestinal manifestations of FAP, so in these patients, beside annual colonoscopic examination, other examination, such as ophtalmological assessment, abdominal ultrasound, measurement of serum CEA (carcinoembryonic antigen) and alpha-fetoprotein concentrations and thyroid gland examination should be considered.