Casing is an important process in the cultivation of milky mushroom and it greatly determines the yield of the mushroom. The current investigation was undertaken to determine the effect of casing layer thickness in the growth and yield of Calocybe indica, an indigenous tropical edible mushroom. The pure culture was grown in potato dextrose agar medium and maintained. The spawn of Calocybe indica was prepared from the pure culture using white sorghum seeds as substrate. The spawn was inoculated in the paddy straw substrate filled bags and maintained in the mushroom cultivation chamber for the spawn running and growth of mushrooms. After the complete mycelium spreading in the bags, the casing process were done with varying thickness of casing layer viz. 1.5, 2.5 and 3.5 cm. The bags were monitored for the growth of the mushrooms and yield in each of the bags were recorded. The bags with casing layer thickness of 2.5 cm recorded the maximum yield and bioefficiency.