This study is concerned with thermal processing of polyvinylchloride (PVC) in the presence of alkaline oil shale ash. Solid heat carrier (Galoter process)- type oil shale retorting units, where the feedstock is heated by mixing with ash from retorted feed-stock combustion, are potentially an alternative for polyvinylchloride waste recycling. A bench-scale experimental study was performed to investigate the fate of chlorine in co-pyrolysis of kukersite oil shale ash and PVC waste. Experiments were conducted by applying two sequential laboratory-scale batch processes: pyrolysis of PVC waste (70% PVC) with oil shale ash in a Fischer retort (standard method) followed by solid residue combustion in a muffle furnace.