Abstract: A process for desulfurizing carbonaceous material containing inorganic bound sulfur, organic bound sulfur, or conbinations thereof. The process comprises reacting the carbonaceous material at desulfurization conditions with a hydrogen source material in the presence of a reaction accelerator to enhance production and reactivity of atomic hydrogen supplied by the hydrogen source. The reaction is prefereably carried out in the presence of a flowing reaction medium which carries away hydrogen sulfide products and other volatile desulfurization products separating them from the carbonaceous material.