Abstract: A cassette intended for building up drawer cabinets, in which a drawer having a frontal piece is included, a lock is included in the drawer for locking of the same in the cassette. The lock includes a house located inside the frontal piece of the drawer and in connection with an opening therein, inside which house there is a spring-loaded plunger, which is movable vertically in relation to a hole in a bottom piece of the drawer, between a lower, locking position in which a free end of the plunger is behind and below an upper edge of a flange in a frontal frame of the cassette, and an upper, opening position in which the free end of the plunger is located above the flange and goes free therefrom. By the location thereof in the bottom part of the drawer, the lock guarantees that heavily loaded thereby deformed drawers do not risk to unintentionally be pulled out from the cassette.