Abstract. Hypoxic patients with coronavirus disease 2019 (COVID-19) are at high risk of adverse outcomes. Inhaled nitric oxide (iNO) has shown anti-viral and immunomodulatory effects in vitro. However, in vivo evidence of efficacy in hypoxic COVID-19 is sparse. This open label feasibility study was conducted at a single referral center in South India and evaluated the effectiveness of repurposed iNO in improving clinical outcomes in COVID-19 and its correlation with viral clearance. We recruited hypoxemic COVID-19 patients and allocated them into treatment (iNO) and control groups (1:1). Viral clearance on day 5 favored the treatment group (100% vs 72%, P