Assisted living is regulated differently in each state. In most states, assisted living is licensed as a single entity that provides housing and services to residents. However, in a growing number of states a new model of assisted living has emerged, in which the housing and services are separate. In this model, the building is not licensed, but instead makes arrangements with licensed service agencies to provide services to residents. Findings are based on a review of the laws and regulations and interviews with key informants in four states.