In cattle, the chemical composition of the carcass is usually evaluated from one of three reference methods (rib dissection, specific gravity or a combination of easily obtained measures) or is estimated from proxy traits (USDA yield grade (YG), subcutaneous fat thickness (SFT)). Objectives were to evaluate if the relationships between the chemical composition of the carcass and each of the proxy traits (YG, SFT) differed depending on the reference method. The study was conducted by meta-analysis from published results using 25 publications that reported carcass composition and proxy traits (53%, 31% and 16% of the data were based on rib dissection, specific gravity and combination of easily obtained measures, respectively). Results showed that the amounts of carcass fat or protein that can be predicted from a given proxy trait (YG or SFT) differ significantly with the reference method used to determine carcass fat or protein.