On May 22, 2020, this report was posted as an MMWR Early Release on the MMWR website (https://www.cdc.gov/mmwr). On March 28, 2020, two residents of a long-term care skilled nursing facility (SNF) at the Veterans Affairs Greater Los Angeles Healthcare System (VAGLAHS) had positive test results for SARS-CoV-2, the cause of coronavirus disease 2019 (COVID-19), by reverse transcription-polymerase chain reaction (RT-PCR) testing of nasopharyngeal specimens collected on March 26 and March 27. During March 29-April 23, all SNF residents, regardless of symptoms, underwent serial (approximately weekly) nasopharyngeal SARS-CoV-2 RT-PCR testing, and positive results were communicated to the county health department. All SNF clinical and nonclinical staff members were also screened for SARS-CoV-2 by RT-PCR during March 29-April 10. Nineteen of 99 (19%) residents and eight of 136 (6%) staff members had positive test results for SARS-CoV-2 during March 28-April 10; no further resident cases were identified on subsequent testing on April 13, April 22, and April 23. Fourteen of the 19 residents with COVID-19 were asymptomatic at the time of testing. Among these residents, eight developed symptoms 1-5 days after specimen collection and were later classified as presymptomatic; one of these patients died. This report describes an outbreak of COVID-19 in an SNF, with case identification accomplished by implementing several rounds of RT-PCR testing, permitting rapid isolation of both symptomatic and asymptomatic residents with COVID-19. The outbreak was successfully contained following implementation of this strategy. VAGLAHS includes 150 long-term care beds in three SNF patient care areas, or wards; SNF wards A and B are in building 1, and ward C is in building 2. Buildings 1 and 2 do not share common areas, but residents might have indirect contact with outside persons while receiving medical services such as dialysis. These wards admit residents who require intravenous antibiotics, complex wound care, other rehabilitation needs, routine dialysis, chemotherapy, or radiation therapy; underlying conditions, including chronic obstructive pulmonary disease, hypertension, cardiovascular disease, and chronic kidney disease, are common. At the time of the outbreak, 99 (66%) beds were occupied; >95% of residents were men aged 50-100 years. All data were abstracted from the VAGLAHS