In diplomacy, a chargé d'affaires (French for "charged with (in charge of) matters"), often shortened to simply chargé, or CDA, is a diplomat – usually a diplomatic secretary, counselor or minister – who heads a diplomatic mission (e.g., an embassy) in the absence of its Chief of Mission (e.g., an ambassador).
A chargé d'affaires represents his or her nation in the country they are accredited to, and enjoys the same privileges and immunities as a regular ambassador. However, chargés d'affaires are outranked by ambassadors and have lower precedence at formal diplomatic events. In most cases, a diplomat would only serve as a chargé d'affaires on a temporary basis in the absence of the ambassador. In unusual situations, a chargé d'affaires may be appointed for an indefinite period, in cases where disputes between the two countries make it impossible or undesirable to send agents of a higher diplomatic rank.
Chargés d'affaires ad interim ("a.i.") are those who temporarily head a diplomatic mission in the absence of the accredited head of that mission. It is usual to appoint a counsellor or secretary of legation to be chargé d'affaires ad interim, and he is presented to the foreign minister of the receiving state by the former head of mission before he leaves his post. Chargés d'affaires ad interim are not themselves deemed to be formally accredited, as they do not possess diplomatic credentials.