We compared rates of emergency department visits or hospitalizations among ambulatory coronavirus disease 2019 (COVID-19) patients treated with monoclonal antibody (mAb) therapy (n=305) vs untreated patients (n=6354). Treatment was associated with decreased encounters within 30 days (adjusted odds ratio, 0.23 [95% confidence interval,. 15-.36]). Our findings support treatment of acute COVID-19 with mAbs.