A retrospective review of patient medical records was conducted to assess what factors influence the outcomes of diabetic foot ulcers treated with hyperbaric oxygen (HBO) therapy. Patients referred to the Diving Diseases Research Centre for HBO therapy for the treatment of diabetic foot ulcers during a 2‐year period were included in this study. Data collected from 30 sets of patient records were entered into SPSS and statistical analysis was undertaken to investigate whether any underlying pathologies or confounding factors appeared to influence patient outcome. A 73·3% of patients achieved a successful outcome of partial healing, major amputation no longer required, amputation level lower than anticipated prior to HBO or healing at the end of HBO therapy and 70% remained successful 3 months later. A 13·3% of patients were lost to follow‐up at 3 months and one patient (3·3%) had a major amputation. Steroid therapy, peripheral vascular disease, previous minor amputation, type of diabetes, previous HBO therapy, larvae therapy, the use of interactive dressings and haemoglobin A1c levels were all observed to have had a significant relationship with patient outcome (P < 0·05). These results were compared with data from other published research conducted in this area on similar patient groups. A larger scale study focussing on the factors found to be significant in this study is recommended. An improvement of patient documentation would allow patient outcomes to be more consistently monitored in the future.