In the Philippines, mushrooms are cultivated using different formulated cellulosic substrates and the liquid cultivation of mycelial biomass as source of natural bioactive compounds is less intensively practiced. Herein, this present work demonstrated the optimization of liquid culture conditions for the mycelial biomass production of C. cinerea intended for the elucidation of active chemical components with important biological activities. The maximum yield of mycelial biomass of C. cinerea was attained when grown in potato sucrose broth with pH 7.5 and incubated in room temperature (30°C), alternating light and dark, and agitated at 70 rpm condition. Mycelia produced in static condition had higher radical scavenging activity (91.43%) than the culture spent. In contrast, culture spent had higher total phenolic content (210 mg AAE/g sample) than its mycelia. However, in agitated liquid culture, culture spent showed higher radical scavenging activity (77.14%) and total phenolic content (235 mg AAE/g sample) than its corresponding mycelia, which is a strong evident of the oozing of active metabolites from mycelia to the culture spent. Mycochemical analysis revealed that mycelial biomasses produced in both static and agitated condition contained varying amounts of saponins, flavonoids, cardiac glycosides, alkaloids and terpenoids, which are known for their numerous biological activities. Therefore, the established optimum liquid culture of C. cinerea is useful not only for mycelial biomass production but most importantly as a natural resource of bioactive metabolites. Evaluation of other functional bioactivities of the liquid culture of C. cinerea using the optimum culture conditions is currently under investigation.