Apparatus for applying noise-reducing elements to a tyre for vehicle wheels that has a radially inner surface with a service area and a circumferential dimension. The apparatus determines the position in circumferential direction of the service area, determines the position in circumferential direction of a target area on the radially inner surface of the tyre based on the position in circumferential direction of the service area, and applies a noise-reducing element the target area. The position in circumferential direction of the service area is determined by circumferentially inspecting the radially inner surface of the tyre starting from a reference position, detecting the angular position of the service area with respect to the reference position and determining the position in circumferential direction of the service area based on the angular position and on the circumferential dimension of the radially inner surface of the tyre.