The aim of this study was to explore medical social workers' perceptions of evidencebased practice (EBP), including factors relevant for the successful implementation of evidence into medical social work practice. Eight focus group interviews were conducted that included 27 medical social workers. Data were analyzed using qualitative content analysis, which resulted in two categories: "knowledge in practice" and "challenges in relation to the implementation of EBP" and four subcategories: "practice based on research evidence or experience", "obtaining new evidence of practice", "research and the social work context", and "barriers and facilitating factors". Participants tended to perceive EBP as theoretical and positivistic while perceiving their own knowledge as eclectic and experience-based. Although they perceived the relevance of research findings to their clinical practice, they expressed a need for support to translate research into policy and practice. They also reported that studies about their specific work were scarce. The medical social workers' suggestion for the facilitation of knowledge exchange needs further investigation.