To provide a basic information on the chemical concentrations of different raw materials used in mushroom cultivation, the raw materials were collected from 13 Flammulina velutipes, 14 Pleurotus eryngii, and 8 P. ostreatus farms and analyzed to calculate moisture contents, pH, total carbon(T-C), total nitrate(T-N), total phosphate(T-P) and 13 different cations. In our results, the C : N ratios of cotton seed meal, beet pulp, and corn-cob were 6~17, 12~29 and 56~127, respectively. Depending on the companies which process these materials, the range of C:N ratio of soybean curd residue was approximately either 8~9 or 14~17 with wider range of C : N ratio of the raw materials imported from other countries without the detection of heavy metals. In this study, the formula was provided to calculate the composition of mixed media for mushroom cultivation based on the ingredient chart of different raw materials.