Mushroom cultivation has been started recently in Bangladesh. Awareness of the nutritional and medicinal importance of mushrooms is not extensive. In this study, the nutritional values of dietary mushrooms- Pleurotus ostreatus, Pleurotus sajorcaju, Pleurotus florida and Calocybe indica that are very popular among the cultivated mushrooms in Bangladesh have been determined. These mushrooms were rich in proteins ($20{sim}25%$) and fibers ($13{sim}24%$ in dry samples) and contained a lower amount of lipid (4 to 5%). The carbohydrate contents ranged from 37 to 48% (on the basis of dry weight). These were also rich in mineral contents (total ash content is $8{sim}13%$). The pileus and gills were protein and lipid rich and stripe was carbohydrate and fiber-rich. The moisture content of mushrooms ranged from 86 to 87.5%. Data of this study suggest that mushrooms are rich in nutritional value.