It is estimated that there are 30-40 million undocumented workers worldwide. Although undocumented migration has become an issue of high international relevance, it has been strikingly understudied in Canada, especially with respect to its impact on health. The purpose of this study is to explore the concept of undocumentedness in Canada through a scoping review of peer-reviewed and grey literature written in English, French, Portuguese and Spanish between 2002 and 2008. The specific aims are to: (i) summarize and disseminate current academic and community-based findings on the health, service access and working conditions of undocumented migrants in Canada; (ii) examine the sources and use of evidence; (iii) identify significant gaps in existing knowledge; (iv) set recommendations for policy and research, including considerations on transnationalism, ethics, interdisciplinary approaches, gender differences, resilience, and impact on the children of non-status parents.