The aim of this study was to investigate the quality of beef sausages containing mushroom (Agaricus bisporus) powder (MP) with varying rates (0, 0.5, 1.0, and 1.5 %) under cold storage for 60 days. In particular, the study focused on changes to the jelly and fat separation (JFS) of sausage batter, as well as chemical, lipid oxidation, color, and sensory characteristics in the final product. The incorporation of MP resulted in a decline in the JFS, with the most notable reduction occurring at 1.5 % MP, from 10.92 to 7.67 % within the batter. The protein content of the sausage increased from 13.46 % to 15.76 % with the addition of 1.5 % MP. The pH level, which was elevated due to the existence of basic amino acids in MP, decreased during the storage period and reached a pH value comparable to that of the control. The considerable rise in thiobarbituric acid reactive substances (TBARS) observed in the control sausages showed a marked decrease throughout the storage period in the sausages to which MP had been incorporated. Additionally, these sausages exhibited a lower free fatty acid content than the control.