Since button mushroom (Agaricus bisporus) cultivation is performed in closed environment, the understanding of indoor environment becomes essential for the quality and quantitative production of the greenhouse-grown mushroom. To generate information on indoor environmental factors affecting on fruiting body quality, we investigated temperature, humidity, and bacterial concentration and species in a greenhouse located in Buyeo, Chungnam Province. Temperature and humidity were recorded as 19.75 ± 0.35 O C and 87 ± 3.67%, respectively. The total concentration of bacteria was measured as 3.84 × 103 CFU/M 3