A cabinet for electronic devices includes a rack and engaging units. The rack includes a first supporting post, a second supporting post, a third supporting post and a fourth supporting post located at four corners of an imaginary rectangular parallelepiped. An opening is defined between the first supporting post and the second supporting post for the electronic devices inserted therein. Each of the third and fourth supporting posts defines a plurality of pairs of slots therein. The engaging units are mounted on the third and the fourth supporting posts, respectively. Each of the engaging units includes a pair of pins received in a corresponding pair of slots and a pressing element connected with the pins. The pressing element is horizontally moveable by the pins sliding along the corresponding pair of slots to thereby adjust an abutting force between the pressing element and a corresponding electronic device.