In order to gain fundamental knowledge about the co-combustion of coal and waste derived fuels, the pyrolytic behaviors of coal, four typical waste components and their mixtures have been studied by a simultaneous thermal analyzer (STA). The investigated waste components were wood, paper, polypropylene (PE) and polyvinyl chloride (PVC). Strong interactions were observed between PVC & wood, PVC & paper and PVC & coal. Interactions were also observed between PE & wood, PE & PVC, PE & paper and PE & coal, but to a smaller degree. No interactions were observed between coal & wood, coal & paper and wood & paper. Since PVC was the only waste component to interact strongly with coal, the interaction between coal and a real waste mixture might be similar to the interaction observed between PVC & coal.