A machine for making absorbent sanitary articles which includes an absorbent pad in turn including one or more absorbent materials; the machine includes a line for feeding at least one continuous web of impermeable material and at least one unit for forming and applying a succession of absorbent pads along the continuous web of impermeable material and a device for detecting at least one between the weight, density profile (or weight profile) parameters of at least one of the absorbent materials defining the absorbent pad the detecting device including at least one microwave resonator.