Forty patients with mild-to-moderate carpal tunnel syndrome (both unilateral and bilateral cases were included) were randomized to receive an ultrasound-guided injection of ozone (n=20) or corticosteroid (triamcinolone; n=20). The primary outcome of interest included pain on a Visual Analogue Scale (VAS). Secondary outcomes of interest included the Boston Carpal Tunnel Questionnaire symptom severity (BCTQ-SS) and functional status (BCTQ-FS) scores, electrodiagnostic testing for sensory nerve action potential (SNAP) and compound motor action potential (CMAP) latency and amplitude, nerve circumference, nerve area, and the incidence of adverse events. Outcomes were assessed 6 weeks and 12 weeks post-injection. Results revealed statistically significant improvements from baseline in VAS pain scores, BCTQ-SS scores, and BCTQ-FS scores in both groups at 6 and 12 weeks post-injection (p<0.05 for all). However, SNAPs latency, CMAPs latency, and median nerve circumference were statistically significantly improved from baseline in the corticosteroid group only (p<0.05 for all). No statistical significant differences from baseline were observed in either group for SNAPs amplitude and CMAPs amplitude at both 6 and 12 weeks post-injection (p>0.05 for all). The median nerve area was statistically significantly improved from baseline in both groups at 6 weeks post-injection (p<0.05 for both), but only in the corticosteroid group at 12 weeks post-injection (p<0.05). Moreover, no cases of adverse events were observed in either group in the 12 week follow up period.