A high molecular weight aromatic polyether-ketone has been prepared by polycon-densation of diphenyl ether with m-phthalyl chloride under conventional coditions. Ethy-lene dichloride was chosen as the media and aluminum chloride as the catalyst in the polycondensation. It was found that the remainder of aluminium chloride in the product was conveniently removed by treating the reaction mixture with nitrobenzene. Analysis of infrared spectra indicates that not only para-but also orthopositions of the benzene rings of the aromatic ether take part in the polycondensation. The chief pro-perties of the polyether-ketone are listed.