Background: Medical ozone is a chemical agent that consists of three oxygen atoms and has antioxidant, angiogenic and vasodilator effects. This study evaluated the effects of medical ozone pre-treatment on flap survival. Materials and methods: Rats were divided into four groups of 10 rats each and a 9 x 3 cm McFarlane flap was used. Sham group: Neither surgical nor ozone pretreatment was used. Control group: No pretreatment was used after surgery. Preoperative ozone group: Preoperative 1 mg/kg ozone was given intraperitoneally for 7 days. No pretreatment was used after surgery. Postoperative ozone Group: Postoperative 1 mg/kg ozone was given intraperitoneally for 7 days. After postoperative 1 week, all groups were evaluated by surface area measurement, histopathology and electron microscopy. Results: With the experimental McFarlane flap model, the experimental groups had better surface area measurements, along with histopathological and electron microscopic results when compared with the control group. Conclusion: Medical ozone had positive effects on flap survival due to its antioxidant, angiogenic and vasodilator qualities.