Mushroom is a popular nutrient and protein-rich food of the world. Oyster mushroom is the second most popular mushroom after button mushroom all over the world. Oyster mushrooms are the important and least expensive to grow, they are well known for conversion of crop residues to food proteins. Growing medium of the mushroom is generally known as substrate. It is the base of mushroom cultivation same as soil for crops. The present investigations were carried out on Comparative studies of span growth on different grains substrate in three Pleurotus spp. (Pleurotus florida, Pleurotus flabellatus and Pleurotus sapidus). | Comparative studies of span growth on different grains substrate in three pleurotus spp. Pleurotus florida Pleurotus flabellatus and Pleurotus sapidus