The presence of pyrolytic carbon deposits can cause a number of serious problems in the operation of a coke oven. The main objective of the investigation was to study the nature and characteristics of pyrolytic carbon deposits in industrial coke ovens, with particular emphasis on the nature of the carbon deposited adjacent to the oven walls. Study of the carbon deposits by optical microscopy and SEM showed a variable concentration of carbon entities as well as differences in packing density.The European Community, the Research Programme of the Research Fund for Coal and Steel, IMPECABL Project, contract number RFCR-CT-2004-00004Peer reviewed