Different nutrition assessment tools and definitions are proposed for cancer-associated malnutrition and wasting (cachexia). We studied the associations between these assessments and overall survival in stage IV colorectal carcinoma patients. Anthropometric measures, energy intake, biochemical variables, nutritional risk screening, assessment of malnutrition, cachexia and body composition from computed tomography images were analysed, in 77 patients from Norway and Canada. Results were dichotomized into presence or absence of nutritional risk, malnutrition, cachexia and sarcopenia (low muscle mass) and associated with survival. Overall, 22% up to 55% of the patients had cachexia according to different cachexia criteria: 34% were malnourished, 42% were at nutritional risk, and 39% were sarcopenic. Forty-four percent of the patients did not meet criteria for any of these conditions. Patients with cachexia defined by Cancer Cachexia Study Group (CCSG) had shorter survival in an unadjusted analysis, [Hazard ratio (HR) = 2.43; 95% confidence interval (CI) 1.32-4.47; P = 0.005]. After adjusting for nation, age and gender, cachexia (HR = 2.26; CI 1.18-4.32; P = 0.014) and malnutrition (HR = 1.83; CI 1.06-3.13; P = 0.029) remained significant predictors of survival. Nutritional depletion in up to 55% of the patients was found. The lack of concordance between the results obtained by different assessment criteria was obvious. CCSG's cachexia score was the best prognostic factor for overall survival.