Abstract: A lock for a cabinet cassette having a drawer comprises a frame structure which carries on one hand a locking bar (47) passing through an opening (50) in a frontal part (23) of drawer, said bar being turnable and projecting from the inside of said frontal part (23), and on the other hand a handle connected to the bar. At least one fixed projection (54) is connected to the frame structure, said projection projecting from the back side of the frontal part, the locking bar (47) being, by turning the handle (48), movable between on one hand a locking turned-up position in which the bar engages behind an upper vertical flange (16) of the frontal frame (6) of the cassette and on the other hand a liberating turned-down position in which the bar is located below the upper side (55) of the projection (54).