Primary signet ring cell carcinoma of the colorectum detected at an early stage is very rare; most cases are detected at an advanced stage. Therefore, its progno-sis is poorer than that of ordinary colorectal cancer. A 56-year-old Korean man was seen at this hospital for management of signet ring cell carcinoma of the co-lon. Colonoscopic examination revealed a Ⅱa-like, ill-defined and flatly elevated 9-mm residual tumor in the cecum. Endoscopic mucosal resection was preformed. Pathological examination of the resected specimen re-vealed signet ring cell carcinoma that had invaded the lamina propria without venous or perineural invasion. Abdominal computed tomography (CT) and positron CT showed no evidence of primary lesions or distant me-tastasis. An additional laparoscopic right-hemicolectomy was performed; no residual tumor or lymph node me-tastasis was found. We report a case of primary signet ring cell carcinoma of the colon detected at an early stage and provide a review of the literature. Primary, signet ring cell carcinoma of the colorectum detected at an early stage is very rare; most cases are detected at an advanced stage. Thus, its progno-sis is poorer than that of ordinary colorectal cancer. A 56-year-old Korean man was seen at this hospital for management of signet ring cell carcinoma of the co-lon. Colonoscopic examination revealed a IIa-like, ill-defined and flatly elevated 9-mm residual tumor in the cecum. Endoscopic mucosal resection was preformed. Pathological examination of the resected specimen re-vealed signet ring cell carcinoma that had invaded the lamina propria without venous or perineural invasion. Abdominal computed tomography (CT) and positron CT showed no evidence of primary lesions or distant me-tastasis. An additional laparoscopic right-hemicolectomy was performed ; no residual tumor or lymph node me-tastasis was found. We report a case of primary signet ring cell carcinoma of the colon detected at an early stage and provide a review of the literature.