Abstract: The present invention provides a locking device based on a rack and pinion mechanism for securing a double door system, for example cabinets with double door. The locking system comprises a pair of jaws extending from a central housing and adapted to mount over the two handles of double door and the jaws are operably coupled to a gear assembly enclosed in the central housing. The gear assembly could be cranked to move the jaws laterally in extended and retracted position for tightening and loosening the locking device over the handles.