The specification describes a method and a system for measuring the wear of a disk of composite ceramic material of a disk brake. The method comprises the following operations: measuring the temperature (T) of the disk at a predetermined frequency (f), calculating a wear increment (delta i) as a function of the measured temperature (T) at every temperature measurement, summing the calculated wear increments (delta i) comparing the sum of the wear increments with a predetermined limiting wear index (i lim) and signalling the eventual overstepping of the limiting wear index (i lim).