Besides strict requirements for landfills the EU has also established criteria and procedures for the acceptance of waste delivered to landfills. Hazardous waste landfilled must meet the relevant waste acceptance criteria, which, besides standards for physical stability, consist of quantitative limits for leachable substances and organic matter. Evaluated testing methods-batch tests and a percolation test-were used in this investigation to study the leaching behaviour of oil shale semicoke. The results obtained indicate that none of the leaching limit values for inorganic components were exceeded in the analysed semicoke samples. The influence of recarbonation on the leachability of different components from semicoke was also studied.