The Office of Coal Research, Department of the Interior, sponsors research and development to encourage and stimulate the production and conservation of coal in the United States. ARCO Chemical Company, a Division of the Atlantic Richfield Company, and FMC Corporation have been carrying out research and development under Project Seacoke and Project COED, respectively. One of the products from the COED process is a coal-derived oil intended to be asynthetic crude oil. The Seacoke process would also produce a similar material. ARCO, as part of their job, was charged with advancing knowledge in the field of hydrotreating materials such as would be derived from these two processes. Accordingly, the following work was carried out by ARCO under their OCR-sponsored project utilizing oil produced by the COED process. As produced, the coal-derived oil has a low hydrogen content and a high concentration of heteroatoms, making it unsuitable for use in many existing refining processes. Hydrotreating of the oil is required to alleviate these shortcomings. Treating was carried out in a continuous downflow system employing a recycle hydrogenstream. Throughout the program, a single catalyst, HDS-3A, manufactured by American Cyanamid, was used. It is a 1/16-inch extrudate containing 3.0% NiO and 15.0% MoO3 on alumina.