Hyperbaric oxygen therapy (HBO) is a short-term, high-dose oxygen inhalation and diffusion therapy, delivered systemically through airways and blood under high pressure using hyperbaric chambers. HBO stimulates angiogenesis, reduces edema, augments granulation tissue formation by enhancing fibroblasts, and improves leukocyte function by elevating the partial pressure of oxygen in tissue. The number of clinical trials evaluating the effect of HBO on the healing of diabetic foot ulcers is increasing, and to date two double-blind randomized controlled trials have been published, both showing improved long-term healing after HBO.