Emerging research on religion, spirituality, health, and mental health has begun to catch the attention of helping professionals. Some clients are expressing a desire for their health and mental health practitioners to initiate discussion of their religious or spiritual beliefs as they relate to their case. Social workers are the most represented group among personnel providing mental health services, so it is important to understand their attitudes, views, and behaviors regarding integrating clients' religion and spirituality (RS) into practice. Few studies have assessed such an integration; those that are available focus primarily on practitioner characteristics and use of specific helping activities to integrate clients' RS in treatment. This article discusses how RS have been integrated into social work practice and education and reviews instruments used to assess such practices. In addition, the findings from previous studies examining social workers' integration of clients' RS are compared with those of other helping professions. Finally, implications for education and practice are discussed.