Administrative Code of 1987
Section 4. Organizational Structure. - The Department shall be composed of:
(1) The Department Proper consisting of the Office of the Secretary, the Offices of the Undersecretaries and Assistant Secretaries, the Internal Audit Service, Monitoring and Information Service, Planning Service, Comptrollership and Financial Management Service, Legal Service, and the Administrative and Manpower Management Service;
(2) The Bureau of Research and Standards, Bureau of Design, Bureau of Construction, Bureau of Maintenance, and Bureau of Equipment; and
(3) The Field Offices, consisting of fourteen (14) Regional Offices composed of Region I (Ilocos), Region II (Cagayan Valley), Region III (Central Luzon, National Capital Region), Region IV-A (Southern Tagalog Mainland Provinces), Region IV-B (Southern Tagalog Island Provinces), Region V (Bicol), Region VI (Western Visayas), Region VII (Central Visayas), Region VIII (Eastern Visayas), Region IX (Western Mindanao) Region X (Northeastern Mindanao) Region XI (Southern Mindanao) and Region XII (Central Mindanao), and their respective District Offices.