A machine for the preparation of beverages by infusion using cartridges; the machine includes an infusion assembly; characterized in that the infusion assembly includes: a slide for introduction of a single cartridge; a lever for operation of a piston; the piston suitable to move rectilinearly along a direction and having a first resting position and a second working position; a chamber suitable for receiving the cartridge; the slide being positioned in an intermediate position between the first resting position and the second working position; the slide having a predefined resting position so that the capsule is positioned resting on an edge of the chamber.