The purposes of this paper are to review the best evidence supporting the use of hyperbaric oxygen therapy (HBOT) in delayed radiation injuries in gynecologic malignancies and report the incidence of radiation injuries at two large medical centers in southeastern Wisconsin. A literature search was performed on Google Scholar, PubMed, and Ovid for studies evaluating the use of HBOT radiation cystitis, proctitis, and necrosis. The studies were then reviewed for the highest quality evidence using American Academy of Neurology guidelines. To evaluate radiation injuries, cancer databases at Froedtert Memorial Lutheran Hospital (FMLH) and Aurora St. Luke's Hospital (ASLH) were accessed. Several studies support the use of HBOT in treating radiation cystitis, proctitis, and necrosis, with proctitis having the strongest evidence in its favor. The average annual incidence of radiation injury at FMLH was 13.8%. Patients with cervical cancer and vulvar cancer had rates of 23% each. The average annual incidence of radiation injury among gynecologic cancer patients at ASLH was 5.5%. There is level A evidence for using HBOT to treat radiation proctitis. There is level B evidence for using HBOT to treat radiation cystitis and necrosis. The incidence delayed radiation injuries can be as high as 23%. This has relevance in practice guidelines for the treatment of delayed radiation injuries in gynecologic malignancies.