Through this qualitative, empirical study the authors aim to explore and describe the sources of knowledge that are used to guide intervention practice by social workers in Chile. Particular attention was paid to factors that may facilitate or hinder the use of research-based evidence to guide social interventions design, implementation, and outcome evaluation. In order to explore these issues, 25 semi-structured interviews with social workers from Chilean social service non-profit organizations were conducted. The main findings suggest that social workers do not use research-based evidence to support their social interventions due to various personal organizational constraints (e.g., lack of time, lack of access to resources for disseminating evidence, lack of English command). In addition, no evaluation processes of social programs which will support evidence-based effectiveness could be found. One key barrier to support use of evidence and evidence production may be related to the fact that most non-governmental organizations maintain a hierarchical and vertical relationship with state agencies (program design, oversight, and funding) for social program development.