Violence in close relationships (VCR) is a major social problem, and calculations indicate that every third woman globally has been subjected to VCR at some point in her life. Given the extent of the problem, it is likely that many social workers will meet victims of violence in their daily work. Their knowledge on VCR are therefore of great importance. The aim of this study was to examine the professional knowledge on VCR among social workers in the Swedish social services. The results are based on a survey answered by 153 social workers in three Swedish municipalities. The results revealed that in social workers’ acquisition of knowledge, they value professional experience and education the most. Around 70 percent stated that they lack knowledge on several topics related to VCR, such as the special needs of targeted groups. In order for social workers to maintain a high professionalism in their work with VCR educational efforts are required, it is also necessary to provide time and conditions for supervision and critical reflection in ongoing work. An important area for future research is to examine how social work education addresses these issues, the conditions for continuing education and training in the social service.