Mushrooms constitute an integral part of the normal human diet and in recent times, the amounts of consumption have been raised greatly, which includes variety of species. The genus Pleurotus comprise about 40 different species that are commonly referred to as “Oyster mushroom”. Among several species of this genus, Pleurotus ostreatus (P. ostreatus) is popularly consumed by all over the world due to their taste, flavor, high nutritional values and medicinal properties. Because of the presence of numerous nutritional compositions and various active ingredients in P. ostreatus, have been reported to have antidiabetic, antibacterial, anticholestrolic, antiarthritic, antioxidant, anticancer, eye health and antiviral activities. In this review, we particularly expose the high nutritional values of P. ostreatus, in relation to their potential medicinal usage which suggest that the P. ostreatus mushrooms are the most important nutraceutical functional foods.