We performed D2 low anterior resection in a patient with stage I rectal cancer [pathological diagnosis: proper muscle (pm) invasion, n0, lymphatic invasion (ly), (-); venous invasion (v), (-); anal margin, (-)]. The tumor recurred at the anastomotic site approximately one year later and was treated with Miles' operation [pm, n0, ly (+); v (-); deep border of the primary tumor (-)]. The tumor marker CEA increased to 50.4 ng/ml at four months after surgery and pelvic local recurrence was detected. Since then, the patient has been receiving chemoradiotherapy on an out-patient basis. Cytokeratin immunostaining of all the lymph nodes collected during the two operations showed clusters of occult neoplastic cells (ONCs) in the perinodal fat around the nodes harvested at the first operation. These findings suggest that the risk of local recurrence of rectal cancer is increased even in stage I disease if ONCs are found in the perinodal fat. Further studies are required to examine the relationship between local recurrence and extranodal ONCs in patients with primary rectal cancer.