Cordyceps militaris is a health-promoting mushroom that can be cultivated in laboratory. The purpose of this study was to extract and evaluate the bioactive activity in vitro of proteins extracted from Cordyceps militaris. The extraction times of 2, 4, 6 and 8 hours were investigated. The samples were extracted using 50 mM sodium phosphate buffer solution, pH 7.4 at 4 ?C with the ratio of solid: liquid at 1: 10 (weight/volume; g/ml). The results showed the Cordyceps militaris protein extracts had the bioactive activities, i.e., free radical scavenging of DPPH, ABTS, hydroxyl and superoxide, ferrous-chelating, ferric reducing and fibrinolytic activities. The highest bioactive activity was found in the protein sample with 4 h extraction time (p<0.05). This work revealed that Cordyceps militaris protein extracts possessed potential bioactive activity in vitro, suggesting potential for use of Cordyceps militaris protein extract as a natural bioactive compounds.