A cash drawer is generally a compartment underneath a cash register in which the cash from transactions is kept. The drawer typically contains a removable till. The till is usually divided into compartments used to store each denomination of bank notes and coins separately to make counting easier. The removable till allows moneys to be removed from the sales floor to a more secure location for counting and creating bank deposits.

A cash drawer is usually of strong construction and may be integral with the register or a separate piece that the register sits atop. It slides in and out of its lockable box and is secured by a spring-loaded catch. When a transaction that involves cash is completed, the register sends an electrical impulse to a solenoid to release the catch and open the drawer.

Cash drawers that are integral to a stand-alone register often have a manual release catch underneath to open the drawer in the event of a power failure. More modern cash drawers have eliminated the manual release in favor of a cylinder lock, requiring a key to manually open the drawer. The cylinder lock usually has three positions: locked, unlocked, and release. The release position is an intermittent position with a spring to push the cylinder back to the unlocked position. In the "locked" position, the drawer will remain latched even when an electric signal is sent to the solenoid.