Button mushroom (Agaricus bisporus) regarded as "vegetarian meat" contain 90 per cent moisture and rich in protein, vitamins, fiber and minerals. It produces high quantity and superior quality protein from agro wastes through composting. Research was undertaken to design and develop a compost turner for button mushroom. A mechanical compost turner of capacity 5 tonnes per hour was designed and developed to prepare quality compost. Mechanically turned wheat straw based compost yielded the highest quantity of mushroom at the rate of 12.43 kg per 100 kg of compost. Cost of turner and turning was Rs.65000 and Rs.35/tonne of compost, respectively. The saving in cost and time compared to conventional turning were 45.31 and 87.5 per cent. Hence, for turning and processing button mushroom compost through compost turner would be highly promising and beneficial for medium and small scale mushroom growers. This book narrates the design aspect of various working parts of compost turner and its performance evaluation.