Brain metastases from colorectal carcinoma (CRC) are rare. The objectives of this study are to assess the natural history, outcome, and possible prognostic factors in CRC patients with brain metastases. Between 1995 and 2008, 8,732 patients with CRC were treated at Yonsei University Health System. Brain metastases were found in 1.4% of these patients. Retrospective review and statistical analysis of these 126 patients were performed. Median time from diagnosis of metastatic CRC (mCRC) to brain metastases was 9.0 months (range 0-85 months), and 14 patients (11.1%) had brain involvement as their initial presentation. Among the 126 patients, 91.3% had other systemic metastases; the most common extracranial metastatic site was lung (72.2%). Median follow-up duration was 6.1 months (range 0.1-90.3 months), and median survival after diagnosis of brain metastases was 5.4 months [95% confidence interval (CI) 3.9-6.9 months]. Median survival time after diagnosis of brain metastases was 1.5 months for patients who received only steroids (15.9%), 4.0 months for those who received whole-brain radiation therapy (37.5%), 9.5 months for those who received gamma-knife surgery (GKS) (32.5%), and 11.5 months for those who underwent surgery (20%) (P < 0.001). On multivariate analysis, recursive partitioning analysis (RPA) class and amount of chemotherapy before brain metastasis were independent prognostic factors for survival. Overall prognosis of patients with brain metastases from CRC is poor. Nevertheless, patients with low RPA class, or those with previous less chemotherapy showed good prognosis, indicating that proper treatment may result in improved survival time.