This thesis examines how Naval Construction Forces (NCFs) Operating with Marine Air Ground Task Forces (MAGTFs) receive sustainment support. Restructuring of the military forces, in particular the Marine Corps engineer units, has resulted in an increase in the mission dependent general engineering support that the Seabees provide to MAGTFs. The Seabees have developed a robust initial sustainment capability that serves them well in independent operations, but that can be a significant liability when operating with MAGTFs. This thesis analyzes the impact this robust sustainment capability has on the Seabees when they deploy in support of MAGTFs in terms of mobility and footprint. The research shows that elimination of initial sustainment material from the Seabees can reduce the Aircraft Load (ACL) requirements for the our Navy Mobile Construction Battalions (NMCBs) notionally slated to Support a Marine Expeditionary Force (MEF) by more than 46 C-141B ACLs. Additional savings can be realized by realigning the medical capability of the NMCBs to a configuration similar to a comparable Marine Corps engineer unit. This reconfiguration would save weight and space as well as allow the NCF to eliminate almost $5 million in medical equipment from its NMCBs.