Paddy straw mushroom (Volvariella volvacea) is a world famous edible mushroom variety that has high demand due to its deliciousness and nutritive value. Although there is a big demand in Sri Lanka, there was no proper method of cultivation since it needs high temperature (33-35 °C) and 85-90 % relative humidity in the growing environment Therefore, an experiment was designed at Regional Agricultural Research and Development Centre, Department of Agriculture – Makandura during the year 2009 to develop an indoor (poly house) cultivation method that would maintain above environment requirements.