Desmoids are rare tumors of the connective tissue. It develops about 1:1000 times more in patients with familial adenomatous polyposis (FAP, Gardner syndrome) compared to normal population. It has been shown in molecular genetic examinations, that different mutations of the APC gene are responsible for desmoid tumors in FAP. It means, that this disease is one of the extraintestinal manifestations of Gardner syndrome. This tumor has high recurrence rate and is growing rapidly, and as a result it is the second most common cause of death in FAP patients. That is why genetic examination for FAP patients is advised to decide if the patient has higher risk for desmoid formation. If the result of the genetic test is positive, it is advisable to try to slow the progression of polyposis with medical treatment, and so to delay the date of the colectomy because the surgical intervention--and connective tissue damage--can induce desmoid formation in these patients. At the same time it is reasonable to examine and regularly control patients with sporadic desmoid tumors searching for other manifestations of Gardner syndrome (colon, stomach and duodenum polyposis, tumor of papilla Vateri, retinopathy, etc.). Palliative surgery is not indicated in patients with inoperable intraabdominal desmoid tumors, because partial resections (R1, R2, debulking) result in further tumor progression. In these patients medical treatment (sulindac, tamoxifen), chemotherapy (doxorubicin, dacarbazin) and radiotherapy or combination of them can result tumor remission. We describe our three patients (an abdominal wall desmoid four years following Cesarean section; a desmoid tumor in the retroperitoneum and in the pelvis diagnosed three years after total colectomy; and a retroperitoneal and abdominal wall desmoid one year after total colectomy) and etiology, diagnosis and therapy of desmoid tumors are discussed.