Some psychiatric hospitals have instituted mandatory COVID-19 testing for all patients referred for admission. Others have permitted patients to decline testing. Little is known about the rate of COVID-19 infection in acute psychiatric inpatients. Characterizing the proportion of infected patients who have an asymptomatic presentation will help inform policy regarding universal mandatory versus symptom-based or opt-out testing protocols. We determined the COVID-19 infection rate and frequency of asymptomatic presentation in 683 consecutively admitted patients during the surge in the New York City region between April 3rd, 2020 and June 8th, 2020. Among these psychiatric inpatients, there was a 9.8 % overall rate of COVID-19 infection. Of the COVID-19 infected patients, approximately 76.1 % (51/67) either had no COVID-19 symptoms or could not offer reliable history of symptoms at the time of admission. Had they not been identified by testing and triaged to a COVID-19 positive unit, they could have infected others, leading to institutional outbreak. These findings provide justification for psychiatric facilities to maintain universal mandatory testing policies, at least until community infection rates fall and remain at very low levels.