The CISMIL is the body responsible for the production of the intelligence needed for the fulfillment of specific missions of the Portuguese Armed Forces and for ensuring the military security.
It is part of the General staff of the Armed Forces (EMGFA) and is headed by a major-general or a rear-admiral.
It is the successor of several Portuguese joint military intelligence services that existed in the past, namely the EMGFA 2nd Division (1974–75), the SDCI (1975–1976), the DINFO (1977–93) and the DIMIL (1993–97).
The reorganization of the SIRP, led to the creation of the SIEDM (Military and Defense Strategic Informations Service) in 1997.
The SIEDM became again the SIED (Defense Strategic Informations Service), with the sole role of foreign intelligence.