Button Mushroom (Agaricus spp.) is the most popular mushroom variety grown and consumed the world over. In India, its production earlier was limited to the winter season, but with technology development, these are produced almost throughout the year in small, medium and large farms, adopting different levels of technology. The species being grown in most farms is the white button mushroom (Agaricus bisporus) belonging to Class Basidiomycetes and Family Agaricaceae. They also contain B vitamins as well as a powerful antioxidant called selenium.