Introduction: Cancer-related microangiopathic haemolytic anaemia (CR-MAHA) is a rare paraneoplastic syndrome characterised by tumour driven red cell destruction and platelet consumption which manifests as progressive anaemia and thrombocytopaenia. It is rarely seen in colorectal cancer (CRC). Without prompt anti-cancer therapy it is uniformly fatal, often within days of onset. Case: A previously well woman in her early 50s developed transfusion refractory anaemia and thrombocytopaenia during admission for workup of right sided abdominal pain. Initial CT showed a large ileocaecal mass, bilateral ovarian masses and lymphadenopathy involving the mesentery, retroperitoneum and mediastinum. Haemolysis screen returned positive and blood film demonstrated leukoerythroblastosis - suggestive of CR-MAHA. After multi-disciplinary discussion, D3 hemicolectomy and bilateral salpingo-oophorectomies were performed to arrest the MAHA, with successful resection of all macroscopic intra-peritoneal disease. Despite initial improvement, her MAHA re-worsened on post-operative day 2 and she passed away the following day. Pathology returned as ileocaecal signet ring cell adenocarcinoma, bilateral Krukenberg tumours, microscopic peritoneal metastases and 31/31 lymph nodes involved. Discussion: CR-MAHA uncommonly affects CRC patients. It is typically found in metastatic cancers, commonly of signet ring cell type and is frequently associated with bone marrow metastases which may be occult. Diagnosis requires exclusion of alternative drivers of MAHA. When recognised early, anti-cancer therapies such as chemotherapy and less commonly surgery may salvage some patients, however the disease may be fatal despite aggressive treatment.