A method of producing a monolithic three-way catalyst for the purification of exhaust gases of internal combustion engines. First, a mixed oxide coating is provided to a monolithic carrier by treating the carrier with a coating slip in which an active alumina powder containing cerium in oxide form is dispersed together with a ceria powder and then baking the treated carrier. Next, Pt, Rh and/or Pd are deposited on the oxide coating by a known thermal decomposition process. The addition of the ceria powder to the coating slip is effective in enhancing the CO, HC and NO.sub.x conversions and durability of the produced catalyst at high temperatures. Preferably the content of Ce in the active alumina powder is 1-5 wt %, and, in the coating after baking, Ce of the ceria powder amounts to 5-50 wt % of the coating. Optionally a zirconia powder too may be added to the coating slip such that Zr of the zirconia powder amounts to 1-10 wt % of the coating.