Purpose To compare the efficacy of local ozone injection versus corticosteroid in plantar fasciopathy treatment. Patients and methods This double-blinded randomized trial was performed on 44 adult patients with plantar fasciopathy. One group (23 patients) received local injection of 40 mg methylprednisolone, while a local injection of 3 cc oxygen-ozone solution was performed for the other group (21 subjects). Severity of pain, functional level, and pressure-pain threshold (PPT) were measured before treatment and 1, 4, and 12 weeks after injection using VAS, Foot and Ankle Ability Measure (FAAM) questionnaire, and algometer for PPT, respectively. Results The majority (65.9%) of the total 44 patients analyzed, were women. Both treatments efficiently relieved patients' pain and improved their functions at 1 and 3 months follow-up time-points. But one week after injection, the improvement in VAS ( p <0.001) and FAAM ( p <0.001) was significant only in the corticosteroid group. During the first month, VAS ( p =0.35) and PPT ( p =0.003) were still better in the corticosteroid group. However, FAAM revealed no remarkable difference between the two groups ( p =0.083). Eventually, at the third month of follow-up, there was no remarkable preference between the treatments regarding any of the outcome measures ( p >0.05). Nevertheless, both methods efficiently improved patients' symptoms, ie, over the 50% of pain reduction and 30% improvement in functional status. Conclusion The present results showed no remarkable superiority between the two groups. In other words, although ozone injection showed a slower efficacy than methylprednisolone, it could be used in plantar fasciitis management as an appropriate alternative.