The "Observable Indicators of Nursing Home Care Quality" instrument was developed as a new measure of nursing home care quality. The instrument is based on a theoretical model of quality nursing home care grounded in data from provider and consumer focus groups. The instrument was piloted in 10 Missouri nursing homes. Subsequent versions were tested in 109 Missouri and 11 Icelandic nursing homes. Content validity was established using experts. Concurrent and known groups validity was evaluated using Minimum Data Set quality indicators, survey citations, and a process of care measure. Interrater and test-retest reliabilities were calculated as well as coefficient alpha. The "Observable Indicators of Nursing Home Care Quality" instrument is a new measure that can be used by researchers, and potentially by regulators, consumers, or providers, to observe and score specific indicators of quality care following a 20- to 30-minute inspection of a nursing home.