The effect of the ratio of solvent to coal (S/C) and the period of heating by microwave on the solubilization of Turkish Coals (Beypazari, Bolu-Goynuk, Mugla-Yatagan. Soma-Merkez, Tuncbilek lignites and Zonguldak coal) in tetralin have been investigated. For the investigation of the effect of the S/C ratios with values of 4/1, 5/1, 6/1, 7/1 and 8/1, the coal samples were heated by microwave for 10 min. The results indicated that the optimum S/C ratio depends on the coal type to obtain the highest yields of THF solubles. The effect of microwave heating period was investigated at the values of 4/1 and 8/1 of S/C ratios and the heating period was changed from 2 to 10 min at 2-min intervals. The yield of THF solubles decreased with increasing heating period at the value of S/C ratio of 4/1, they increased with increasing heating period when the value of S/C ratio was 8/1. The yield of THF soluble coal products after 10 min of microwave heating period changed from 13% to 23%, depending on the coal type.