Psychologists who work in hospital settings confront assorted challenges in implementing the scientist–practitioner model. Clinical psychologists must deal with the tension between an evidence-based model and the realities of clinical practice. Psychologists can gain a better understanding of what it means to function as a scientist–practitioner by understanding current debates in both psychology and medicine on the relationship between research and practice. Psychologists are not unique in the slow pace of implementing research into practice. Psychologists in hospitals can make a contribution to the treatment of medical patients by emphasizing the role of the treatment relationship in health-care outcomes. Medicine’s use of practice-based research networks provides a valuable structure for psychologists to emulate in order to function as active participants in the collection of practice-based evidence rather than passively accommodating to the evidence-based clinical practice guidelines.