In 2021 real estate investment trusts (REITs) held investments in 1,806 US nursing homes. REITs are for-profit public or private corporations that invest in income-producing properties. We created a novel database of REIT investments in US nursing homes, merged it with Medicare cost report data (2013-19), and used a difference-in-differences approach within an event study framework to compare staffing before and after a nursing home received REIT investment with staffing in for-profit nursing homes that did not receive REIT investment. REIT investment was associated with average relative staffing increases of 2.15 percent and 1.55 percent for licensed practical nurses (LPNs) and certified nursing assistants (CNAs), respectively. During the postinvestment period, registered nurse (RN) staffing was unchanged, but event study results showed a 6.25 percent decrease in years 2 and 3 after REIT investment. After the three largest REIT deals were excluded, REIT investments were associated with an overall 6.25 percent relative decrease in RN staffing and no changes in LPN and CNA staffing. Larger deals resulted in increases in LPN and CNA staffing, with no changes in RN staffing; smaller deals appeared to replace more expensive and skilled RN staffing with less expensive and skilled staff.