The goal of the work was to develop the physicochemical principles of producing solid composite fuel from oil-shales. It has been experimentally proven that oil-shales and their derivatives can be used as organo-mineral fillers for fuel composite materials with combustible matrices for producing briquettes (press materials). The specific combustion heat of oil-shale composite materials is comparable with that of the traditional kinds of solid fuel (bituminous coal, wood, and peat). Solid oil-slimes (combustible wastes of oil processing and transporting) are recommended to be used as matrices of fuel composite materials. Organic and mineral oxidants are the best modifying agents for oil-slimes, they enhance their heat of combustion. Organic peroxides such as curnol hydroperoxide and benzoli peroxide possess the strongest activating effect. Oil-shales contacts with oils in various oil-fields lead to a substantial enhancement of their heat properties and a decrease of their ash content.