We treated a 59-year-old man with a small, yellowish, submucosal rectal tumour that was detected incidentally during a colonoscopic examination. Endoscopic ultrasonography revealed a hypoechoic submucosal tumour 13 mm in diameter. Computed tomography and magnetic resonance imaging studies were performed, and pararectal and para-obturator lymph node involvement was confirmed. The patient underwent Miles' operation with lymph node dissection; 24 months later, he is disease free. We were able to diagnose rectal carcinoid tumour and evaluate the lymph node metastasis prior to surgery. Even with a small carcinoid, it is important to determine the depth of invasion and the presence of lymph node metastasis prior to treatment.