PURPOSE: Myosteatosis evaluated on computer tomography (CT) scan has gained attention for its prognostic impact in colorectal cancer (CRC) patients. The aims of the review were to explore how myosteatosis is measured and identify any associations between myosteatosis and long-term survival and/or postoperative outcomes in non-metastatic CRC patients. METHOD: A systematic search was performed on Embase, Medline and Cochrane Central Database. Studies that included non-metastatic CRC patients with skeletal muscle attenuation (SMA) evaluated on pre-operative CT scans were included. Studies must specify the diagnostic cut-off values for myosteatosis. RESULTS: Out of 441 articles generated from the search, 15 were included. Myosteatosis was most commonly evaluated at the lumbar 3 level using total-cross sectional SMA. The most commonly used diagnostic criteria were Martin’s definition (SMA < 41 HU for BMI < 25 kg/m2 and SMA < 33 HU for BMI ≥ 25 kg/m2), utilised by 10 studies and Xiao’s definition (SMA <35.5HU for men and SMA <32.5HU for women), utilised by 2 studies. 10 out of 14 studies found a negative association between myosteatosis and overall survival, with hazard ratios ranging from 5.76 to 1.42. Inconsistent associations between myosteatosis and post-operative outcomes was found due to variability in measurement protocols and description of post-operative complications among studies. CONCLUSION: In non-metastatic CRC patients, evidence exists of a negative association between CT-based myosteatosis and long-term survival. However, universal myosteatosis measurement and diagnostic criteria and consistent classification of post-operative complications are needed to further validify the prognostic value of myosteatosis.