PURPOSE: Colorectal cancer might have a synchronous cancer or polyps. Diagnosis of synchronous cancer is important for surgical treatment. The purpose of this study is to review the clinicopathological characteristics of synchronous multiple colorectal cancers. METHODS: A retrospective analysis was performed with 16 patients with synchronous multiple colon cancer out of 625 colorectal cancer patients who underwent surgical treatment from March 2000 to December 2005. RESULTS: The incidence of synchronous multiple colon cancer was 2.6%, and 1.9% in case of exception of Tis. The incidence of synchronous polyp was 62.5% in synchronous multiple colorectal caner and higher than 29.6% in single colorectal cancer. Numbers of the lesions were from 2 to 4, and total number of lesions were 35. Preoperative diagnostic rate of multiple colorectal cancers was 46.7% with colonoscopic examination. 18.8% of synchronous cancers were detected during intraoperative examination. Microscopically, ulcerative type was most common (62.9%), moderately differentiated type was common (84.8%). In TNM stage, advanced stage was common and stage III was 43.8%. T3 was the most common lesion in T stage among all lesions in synchronous cancer. Relatively small lesions of less than 2 cm were common (48.3%). Synchronous cancers were common in distal part of colorectum. Operations were carried out from segmental resection, to total or subtotal colectomy in case of multiple involvement of colon by cancer. During the follow up, one case was died postoperative 22 months due to cerebrovascular attack. CONCLUSIONS: Synchronous multiple colon cancer was important for decision of extent of surgical resection. In this study, preoperative diagnostic rate of multiple colorectal cancers was 42.9%. So, index of suspicion about synchronous multiple colorectal cancers in preoperative and intraoperative stage is major key to improve the detection rate of synchronous lesion and appropriate resection.