Over the past 25 years, the Joint Commission for the Accreditation of Healthcare Organizations has changed its guidelines regarding religious/spiritual care of hospitalized patients to increase attention concerning this aspect of hospital-based care. Little empirical evidence assesses the extent to which hospitals relied on hospital chaplains as care providers during these years. This study investigates (1) the extent of chaplaincy service availability in US hospitals between 1980 and 2003; (2) the predictors of having chaplaincy services in 1993 and 2003; and (3) the change in the magnitude of these predictors between years. This study examines the presence or absence of chaplaincy or pastoral care services in hospitals using the American Hospital Association Annual Survey of Hospitals (ranging from 4,946-6,353 hospitals) in 1980-1985, 1992-1993, and 2002-2003. Between 54% and 64% of hospitals had chaplaincy services between 1980 and 2003, with no systematic trend over this period. In 1993 and 2003, hospital size, location, and church affiliation were central factors influencing the presence of chaplaincy services. Smaller hospitals and those in rural areas were less likely to have chaplaincy services. Church-operated hospitals were much more likely to have chaplaincy services; but between 1993 and 2003, church-operated hospitals were more likely to drop chaplaincy services than to add them. Not-for-profit hospitals were more likely than investor-owned hospitals to add chaplaincy services. Changes to Joint Commission for the Accreditation of Healthcare Organizations policies about the religious/spiritual care of hospitalized patients between 1980 and 2003 seem to have had no discernible effect on the fraction of US hospitals that had chaplaincy services. Rather, characteristics of hospitals, their surroundings, and their religious affiliations influenced whether they provided chaplaincy services to patients.