Although malignant behavior of rectal carcinoid tumors is rare, the risk of metastases and death does exist. Adaptation of therapy according to the estimated malignancy seems necessary. To develop a stage-dependent therapy, 31 patients with rectal carcinoid tumors measuring 5 to 50 mm in diameter were analyzed retrospectively. Malignancy was estimated according to tumor size, infiltration depth, and histopathology. There were 18 tumors within the mucosa and submucosa (T1), 7 tumors with muscularis propria invasion (T2), and carcinoid tumor penetrating the full rectal wall (T3) or spreading to surrounding tissue (T4) in 6 patients. Altogether 20 patients (65%) were treated with a minimally invasive intervention: endoscopic polypectomy (EP) in 12 and transanal excision (TE) in 8 patients. In 11 patients (35%) aggressive surgical procedures--anterior resection (AR) in 4 and abdominoperineal resection (APR) in 7--were performed. After a mean +/- SD follow-up of 86.0 +/- 61.3 months, tumor recurrence was not seen in any of the 20 patients with minimally invasive treatment, and all were still alive. No severe complications associated with surgical procedures were detected. In contrast, 5 of the 10 patients with advanced tumor stage died from their disease despite aggressive surgery (AR, APR). In conclusion, depending on tumor stage, treatment of rectal carcinoids includes EP, TE, or extended resection. Minimally invasive techniques are safe treatments for small to medium-size T1/T2 rectal carcinoids. Extended surgery cannot improve the overall survival of those with advanced tumors (T3/T4, N1, M1) but can be beneficial for preventing local complications.