Compost for the production of Agaricus blazei Murrill mushrooms, is produced from wheat straw, straw-bedded horse manure, chicken manure and gypsum. The substrate is made in two processes called Phase I (anaerobic) and Phase II (aerobic). Phase I includes mixing and moistening of the ingredients and a period of uncontrolled self-heating where temperatures will rise to 80ºC. Phase II starts with a pasteurization period of 8h at 56-60ºC and continues with a conditioning period at 45ºC for up to 7 days until volatile NH3 has been cleared from the process by air. Quality parameters for compost cannot be established directly. Moisture and nitrogen contents and pH can be adjusted at the start of Phase I, but the values will be affected during processing. In this paperwork, we studied the physical properties (water content, electrical conductivity) and chemical composition (pH, organic matter, nitrogen, calcium, magnesium, ammonia) of four recipes of compost: classical, synthetic, mixt and original. During the experience, we recorded every hour the compost and the air temperature and the air relative humidity. The highest yield was obtained on synthetic compost with 42 kg mushrooms on 100 kg of compost.