The DMDC may be something you’ve never heard of, but it’s an entity that affects many of the military personnel who serve our great country. The DMDC stands for the Defense Manpower Data Center. The DMDC works under the Office of the Secretary of Defense and collects all data for the Department of Defense. This includes military personnel information, financial records, manpower and training. The DMDC also tracks all health records of active military members’ families.