Specialty care units (SCUs) in nursing homes (NHs) grew in popularity during the 1990s to attract residents while national policies and treatment paradigms changed. Alzheimer disease has consistently been the dominant form of SCU. This study explored the extent to which chain affiliation, which is common among NHs, affected SCU bed designation. Using data from the Online Survey Certification and Reporting (OSCAR) from 1996 through 2010 with 207 431 NH-year observations, we described trends and compared chain-affiliated NHs with independent NHs. Designation of beds for Alzheimer disease SCUs grew from 1996 to 2003 and then declined. At the peak, 19.6% of all NHs had at least one Alzheimer disease SCU bed. In general, chain affiliation promoted Alzheimer disease SCU bed designation across time, chain size, and NH profit status. During the period of largest growth from 1996 to 2003, the likelihood of designation of Alzheimer disease SCU beds was 1.55 percentage points higher among for-profit NHs affiliated with large chains than independent for-profit NHs (P <.001) and remained 1.28 percentage points higher from 2004 to 2010. However, chain-affiliated NHs generally had a lower percentage of residents with dementia than independent NHs. For example, although for-profit NHs affiliated with large chains had more Alzheimer disease SCU beds, they had nearly 3% fewer residents with dementia than independent NHs (P <.001). We conclude that organizational decisions to designate beds for Alzheimer disease SCUs may be related to marketing strategies to attract residents since adoption of Alzheimer disease SCUs has fluctuated over time, but did not appear driven by demand.