A well characterized coal sample from Egypt was irradiated using Co-60 source for different dwell limes starting from 10 to 100 h in the first experiment and from 7 to 28 days for the second one. The constant dose rates of both were 9.12 and 7.61 Gray/min, respectively. Mossbauer results obtained from the first irradiation process have shown oxidation of pyrite to jar-ache. While ferrous sulfates resulted from pyrite oxidation is clearly evidenced in the irradiated coals from 7 to 28 days. Gamma irradiation as a method for coal desulphurization is discussed.