The proximate composition and nutritional quality of two mushroom varieties cultivated in Egypt (Agaricus bisporus and pleurotus ostreatus) were investigated using standard analytical techniques. The samples of mushroom contained 26.05% and 33.85%,  crude protein in the dried P. ostreatus and A. bisspours   respectively. Crude fat content in mushroom varieties (P. ostreatus and A. bisporus) were almost the same (P > 0.05) and had value of 2.79% and 2.41%, respectively. Also, other proximate composition values were in the following ranges: moisture content 9.65% – 11.81%, ash 5.86% – 7.97%, crude fibre 8.25 – 13.21% and carbohydrate (by difference) 57.05% – 42.56%. for (P.ostreatus and A.bisporus) respectively.  Protein in both of dried mushroom varieties (P. ostreatus and A. bisporus) were slightly lower than FAO/WHO (1973) in total essential amino acids., the total essential amino acids values of dried mushroom  (P.ostreatus and A.bisporus)  were 39.25 and 44.95 gm / 16 gm N, respectively. The results show that histidine scored the highest chemical protein score of 140.38 and 136.15 for dried mushroom varieties Also,  dried mushroom varieties Agaricus bisporus and Pleurotus ostreatus oils had higher amounts of unsaturated fatty acids. Total phenols and antioxidant activity in dried Agaricus bisporus were significantly (P < 0.05) higher than that in Pleurotus ostreatus. The results showed that these nutrient rich mushroom flours under investigation may prove useful in the formulation of different food products such as, retention of flavour and palatability.