Models of telephone crisis intervention in suicide prevention and best practices were developed from a literature review and surveys of crisis centers. We monitored 2,611 calls to 14 centers using reliable behavioral ratings to compare actual interventions with the models. Active listening and collaborative problem-solving models describe help provided. Centers vary greatly in the nature of interventions and their quality according to predetermined criteria. Helpers do not systematically assess suicide risk. Some lives may have been saved but occasionally unacceptable responses occur. Recommendations include the need for quality assurance, development of standardized practices and research relating intervention processes to outcomes. (Contains 2 figures and 4 tables.)