In a method for secondarily locking at least one electrical contact (2) which is inserted into a contact chamber (7) and is primarily latched therein, the at least one electrical contact (2) is, according to the invention, primarily latched in its contact chamber (7) by means of an external latching tool (12) which engages in the contact chamber (7) through a lateral wall opening (11) in the contact chamber outer wall (10) from outside, and the electrical contact (2) is then secondarily locked in its contact chamber (7) before the external latching tool (12) is removed again. The associated contact latching system for an electrical plug connection comprises at least one electrical contact (2) which has an undercut (6) for a primary latching means, a contact chamber housing (1) which has at least one contact chamber (7) for insertion of the electrical contact (2), and at least one locking element (17) for secondarily locking the inserted electrical contact (2) against the fitting direction (3), wherein, according to the invention, a contact chamber outer wall (10) of the contact chamber (7) has a lateral wall opening (11) through which the undercut (6) in the inserted contact (2) is accessible from the outside.