An oxygen delivery system is disclosed. The basis of the oxygen deliver system is a carbide-derived carbon (CDC). The CDC can be tuned to carry O2 directly (CDC OC), or hemoglobin can be adsorbed to provide a hemoglobin-based oxygen carrier (CDC HBOC). The delivery system allows the use of a variety of hemoglobins which differ in their oxygen dissociation profiles, including variant and mutant hemoglobins from other species. The delivery system is biocompatible and stable, and is able to irreversibly bind and hold large amounts of functional hemoglobin variants. The CDC HBOC and CDC OC provide a safe and effective blood substitute for combat casualty care, as well as being useful for oxygen delivery in other contexts.