In the late 1970s, there were fewer than 30 hyperbaric facilities operational in the United States. Most were either military, commercial or highly specialized research facilities. Today an estimated 1,350-plus facilities are in operation. Growth means change. We have seen the primary role of hyperbaric facilities transition from the treatment of diving-related disorders to providing essential primary and adjunctive treatments for multiple medical conditions. Refined research efforts will no doubt validate the continued effectiveness of HBO2 therapy, and perhaps even support new indications for treatment.