Oxidizing pretreatment of low rank coals can enhance their water solubility. Oxidizing species ((OH)-O-., HO2., O-2(.-), H2O2) deriving from the radiolysis of water are also important agents in the decomposition of coal. Radiation treatment of aqueous slurry of lignite and sub-bituminous coal in the dose range of 25-100 kGy increases the absorption of the aqueous phase in the interval of 250-420 nm, showing a maximum at 260 nm. Increased solubility of coal is due to the oxidation of organic material and reduction in the degree of polymerization. Conversion of coal to low molecular weight fuels requires a multistep physical, chemical and biological treatment. Radiation as a physical pretreatment offers an alternative application for coal degradation.