Abstract: A process for isomerizing xylenes, which comprisescontacting an aromatic hydrocarbon feedstock containing mainly a xylene isomeric mixture containing ethylbenzene with a catalyst of a palladium-containing crystalline aluminosilicate in the vapor phase in the presence of hydrogen to continuously isomerize xylenes and simultaneously de-ethylate the ethylbenzene selectively;interrupting the isomerization reaction;introducing an oxygen-containing gas into a bed of the catalyst in which coke has been deposited during the isomerization reaction, to contact the catalyst with the oxygen-containing gas;burning off the coke deposits on the catalyst with the oxygen-containing gas by gradually increasing the temperature of introduction of the oxygen-containing gas from not more than 200.degree. C. to a temperature in the range of 330.degree. to 390.degree. C. with no part of the catalyst bed exceeding a maximum temperature of 400.degree. C. while controlling the hot spot temperature of the catalyst bed not to exceed 50.