BACKGROUND Although sotrovimab reduces the risk of hospitalization or death due to COVID-19, there have been few reports of its use in clinical practice. Particularly, information on the effectiveness of sotrovimab against the omicron variant of the virus is limited. We present 10 cases of COVID-19 treated with sotrovimab at our unit between December 2021 and February 2022. CASE REPORT The age of the patients ranged from 32 to 81 years (median: 40 years). The comorbidities included lung cancer, cardiovascular disease, chronic kidney disease requiring hemodialysis, and AIDS. Two of the patients were also organ recipients. Oxygen saturation (SpO2) was above 97% in all patients. None of the patients presented with pneumonia on admission. However, blood test results showed that all patients had risk factors for severe COVID-19 outcomes. The interval from symptom onset to sotrovimab administration and resolution ranged from 2 to 5 days (median: 2 days) and 2 to 15 days (median: 5 days), respectively. Only 1 patient developed pneumonia and was treated with remdesivir after sotrovimab administration. However, this patient did not require oxygen therapy. Although no moderate to severe adverse events were observed, a mild adverse event was observed in 1 patient. CONCLUSIONS Sotrovimab could be safe and effective in preventing progression of COVID-19 in patients with a variety of underlying diseases and who are at high risk of severe disease outcomes.