A retrospective study of 41 patients with histologically confirmed diagnosis of appendix carcinoid tumors was undertaken by reviewing the surgical records at Massachusetts General Hospital.There were 8 male and 33 female patients (mean age 32 years). Twenty-two patients (54%) presented with signs and symptoms suggestive of acute appendicitis. In 19 patients (46%) the lesions were discovered incidentally. The tumors were located in 32 patients at the tip, in 6 patients in the middle third, and in 3 patients at the base of the appendix. The tumor was less than 1 cm in diameter in 32 patients, between 1 and 2 cm in 7 patients, and was bigger than 2 cm in 2 patients. In 29 patients, the depth of tumor penetration was confined to the submucosa or to the muscle layers of the appendix, and in 8 patients the serosa was involved. In 4 patients, evidence of tumor extension into the meso-appendicular fat was present, including one patient with a tumor bigger than 2 cm and local lymph-node metastases. Forty patients underwent appendectomy alone. One patient with a tumor size bigger than 2 cm in diameter with positive lymph nodes in the mesoappendix underwent secondary right hemicolectomy. Complete follow-up was achieved in 35 patients, and all patients remained free of tumor recurrence.The authors conclude that appendiceal carcinoids are rare and most often are asymptomatic. Tumors of less than 1 cm are adequately managed by appendectomy alone. The appropriate treatment for tumors of 1 to 2 cm continues to be controversial. Right hemicolectomy is recommended for all tumors larger than 2 cm, whereas preference for an aggressive approach should be given in young patients.