Abstract: Pneumo-hydraulic converter for disc brake callipers, particularly for commercial vehicles, comprising a body intended for application directly to a brake calliper or in the immediate vicinity thereof and having a central axis cavity in which there is sealingly slidable a first piston to which is fixed a second piston sealingly slidable in a pneumatic chamber formed at one end of the body and connected at one end to a pressurized air supply and containing a biassing spring for the first and second pistons at its opposite end. The first piston is operatively associated with a hydraulic chamber formed at the other end of the body and defined by a hollow slider guided axially within the body and intended to operate the brake calliper, and the hydraulic chamber is connected to a hydraulic fluid reservoir.