In this study, the mushroom yield, chemical composition and nutritional value of Pleurotus ostreatus (Jacq.) P. Kumm. cultivated in wheat stalk (WS), millet stalk (MS), soybean stalk (SS) and cotton stalk (CS) were determined. Fresh mushroom yield amounts (100 g of substrate, 70% moisture) obtained from WS, CS, MS and SS substrate media were 17.9, 14.3, 22.7 and 31.5 g, respectively. Samples of mushroom cultivated on different culture mediums were analysed for protein, energy, ash, fat, dietary fibre, carbohydrate, moisture, vitamins (thiamin, riboflavin, pyridoxin and niacin) and amino acid contents.