Anaemia is associated with a reduction in quality of life, and is common in patients with colorectal cancer . We recently reported the findings of the intravenous iron in colorectal cancer-associated anaemia (IVICA) trial comparing haemoglobin levels and transfusion requirements following intravenous or oral iron replacement in anaemic colorectal cancer patients undergoing elective surgery. In this follow-up study, we compared the efficacy of intravenous and oral iron at improving quality of life in this patient group. We conducted a multicentre, open-label randomised controlled trial. Anaemic colorectal cancer patients were randomly allocated at least two weeks pre-operatively, to receive either oral (ferrous sulphate) or intravenous (ferric carboxymaltose) iron. We assessed haemoglobin and quality of life scores at recruitment, immediately before surgery and at outpatient review approximately three months postoperatively, using the Short Form 36, EuroQoL 5-dimension 5-level and Functional Assessment of Cancer Therapy - Anaemia questionnaires. We recruited 116 anaemic patients across seven UK centres (oral iron n = 61 (53%), and intravenous iron n = 55 (47%)). Eleven quality of life components increased by a clinically significant margin in the intravenous iron group between recruitment and surgery compared with one component for oral iron. Median (IQR [range]) visual analogue scores were significantly higher with intravenous iron at a three month outpatient review (oral iron 70, (60-85 [20-95]); intravenous iron 90 (80-90 [50-100]), p = 0.001). The Functional Assessment of Cancer Therapy - Anaemia score comprises of subscales related to cancer, fatigue and non-fatigue items relevant to anaemia. Median outpatient scores were higher, and hence favourable, for intravenous iron on the Functional Assessment of Cancer Therapy - Anaemia subscale (oral iron 66 (55-72 [23-80]); intravenous iron 71 (66-77 [46-80]); p = 0.002), Functional Assessment of Cancer Therapy - Anaemia trial outcome index (oral iron 108 (90-123 [35-135]); intravenous iron 121 (113-124 [81-135]); p = 0.003) and Functional Assessment of Cancer Therapy - Anaemia total score (oral iron 151 (132-170 [69-183]); intravenous iron 168 (160-174 [125-186]); p = 0.005). These findings indicate that intravenous iron is more efficacious at improving quality of life scores than oral iron in anaemic colorectal cancer patients.