The coronavirus disease 2019 (COVID-19) pandemic remains a source of considerable morbidity and mortality throughout the world. Therapeutic options to reduce symptoms, inflammatory response, or disease progression are limited. This randomized open-label trial enrolled 100 ambulatory patients with symptomatic COVID-19 in Toronto, Canada. Results indicate that icosapent ethyl (8g daily for 3 days followed by 4g daily for 11 days) significantly reduced high-sensitivity C-reactive protein (hs-CRP) and improved symptomatology compared with patients assigned to usual care. Specifically, the primary biomarker endpoint, change in hs-CRP, was significantly reduced by 25% among treated patients (-0.5mg/L, IQR[-6.9,0.4], within-group P=0.011). Conversely, a non-significant 5.6% reduction was observed among usual care patients (-0.1mg/L, IQR[-3.2,1.7], within-group P=0.51). An unadjusted between-group primary biomarker analysis was non-significant (P=0.082). Overall, this report provides evidence of an early anti-inflammatory effect of icosapent ethyl in a modest sample, including an initial well-tolerated loading dose, in symptomatic COVID-19 outpatients. ClinicalTrials.gov Identifier: NCT04412018.