Dried oyster mushroom (Pleurotus ostreatus) is a raw material used, to a very limited extent, as an additive to food products. The objective of the study was to determine the effect of dried oyster mushroom (Pleurotus ostreatus) added on nutritional value and glycemic index of crackers and bread. The research material consisted of corn crackers and wheat bread baked in a laboratory. The content of protein, fat, dry mass and mineral compounds in the form of ash were determined using standard analytical methods. The content of fibre fractions was determined according to a Van Soest method. The glycemic index (GI) was determined as a percent growth rate of glucose concentration in the blood of people examined after they have eaten particular food products compared to the growth thereof after consumption of glucose. Based on the experiments conducted, it was found that the dried oyster mushroom Pleurotus ostreatus added to crackers and bread enhanced their nutritive value. In those products, there were determined higher contents of protein, insoluble and soluble dietary fibre, and cellulose. The products with the oyster mushroom added were characterized by a lower glycemic index compared to the products without this additive.