Desmoid tumors are known to be associated with Gardner syndrome and, when located in the mesentery, can contribute to morbidity and mortality. Computed tomography (CT) was used to evaluate six patients with Gardner syndrome who, after colectomy, complained either of abdominal pain or of palpable masses. In five patients, desmoids of the mesentery, abdominal wall, and paraspinous muscles were diagnosed; four of these were later proven surgically. The sixth case, with both CT and subsequent surgery negative for desmoid lesions, is included to illustrate the ability of CT to replace exploratory surgery in certain instances. CT provides a relatively noninvasive means of assessing and following patients with Gardner syndrome after colectomy and delaying or preventing further surgery or, if necessary, providing a surgical "road map" to optimize unavoidable procedures.