Colorectal cancer is usually revealed by modifications of bowel habit and/or signs of haemorrhage. Hepatic and lung metastases are the common sites of metastatic involvement of this cancer. Brain metastasis are rare, especially when they are isolated. We report the case of a 37-year-old patient presenting with isolated brain metastasis revealing a rectal cancer. The patient was initially treated by surgical excision of the symptomatic brain metastasis, followed several days later by anterior resection of the rectum and whole-brain radiotherapy. This unusual strategy, due to the lack of preoperative diagnosis, did not improve the poor prognosis of brain metastasis.