The prevention of lipid oxidation is one of the meat industry's target and, consequently, the search for natural antioxidants has been increased in last years. Thus, the aim of this study was to determine the effect of hydroethanolic extract from sun mushroom (Agaricus blazei Murrill) on the oxidative and microbiological stability of pork meat sausage during storage at 4 degrees C. The extract was added to sausages in 0 %, 0.5 %, 1.0 % and 2.0 % (v/w) concentrations. There was done the proximate composition, pH, instrumental color (L*, a*, b*, C* e h*), TBARS (Thiobarbituric Acid Reactive Substances) and microbiological analyzes. Data were subjected to analysis of variance, in randomized completely design. The results from proximate composition and microbiological analyzes at day 0 were according to the Brazilian legislation. At 1st day of storage, control treatment showed higher (p<0,05) a* value (red) than the other treatments, while b* value (yellow) has increased (p<0,05) during the storage period in all treatments. At 21st day of storage, TBARS values of sausages with 2.0 % extract addition was lower (0,705 +/- 0,01 mg MDA/kg sample) (p<0,05) than the control (1,097 +/- 0,11mg MDA/kg sample). The extract has not shown effect on the microbiological stability of the sausages. Nevertheless, the hydroethanolic extract from sun mushroom was effective on the oxidative stability of pork meat sausage when added in a 2.0 % concentration, improving its shelf-life up to 21 days of storage at 4 degrees C, and it is possible the use as a natural antioxidant source.