U.S. Southern Command (SOUTHCOM) has been cited as having mature interagency processes and coordinating mechanisms. As evidenced by the earthquakes that shook Haiti in January 2010, the challenges that SOUTHCOM faces require coordinated efforts from U.S. government agencies, international partners, and nongovernmental and private organizations. This report (1) assesses the extent that SOUTHCOM exhibits key attributes that enhance and sustain collaboration with interagency and other stakeholders and (2) evaluates SOUTHCOM's approach for developing an organizational structure that facilitates interagency collaboration and positions the command to conduct a full range of missions. To conduct this review, GAO analyzed SOUTHCOM documents, conducted interviews with the command and a number of its partners, and visited three U.S. embassies in the Caribbean and Central and South America. GAO recommends that SOUTHCOM (1) revise its Organization and Functions Manual to align structure and manpower to meet approved missions; and (2) identify personnel augmentation requirements for a range of contingency operations, develop plans to obtain personnel, and exercise and assess these plans. DOD concurred with our recommendations and stated it is addressing these issues as quickly as possible.