Retaining social workers in child protection and welfare organisations has been identified as a problem in Ireland (McGrath, 2001; Ombudsman for Children, 2006; Houses of the Oireachtas, 2008) and internationally (Ellet et al., 2006; Mor Barak et al., 2006; Tham, 2006). While low levels of retention have been identified, there is no research that examines the factors in Ireland that influence the retention of social workers. In this thesis, data is analysed from qualitative interviews with 45 social workers in the Health Service Executive South about what influences their decisions to stay in or leave child protection and welfare social work. These social workers’ views are examined in relation to quantitative research on the levels of turnover and employment mobility of child protection and welfare social workers employed in the same organisation. Contrary to expectations, the study found that the retention rate of social workers during the period of data collection (March 2005 to December 2006) was high and that the majority of social workers remained positive about this work and their retention. The quality of social workers’ supervision, social supports from colleagues, high levels of autonomy, a commitment to child protection and welfare work, good variety in the work, and a perception that they were making a difference, emerged as important factors in social workers’ decisions to stay. Perceptions of being unsupported by the organisation, which was usually described in terms of high caseloads and demanding workloads, a lack of resources, work with involuntary clients and not being able to make a difference, were the most significant factors in social workers’ decisions to leave and/or to want to leave. Social workers felt particularly professionally unsupported when they received low quality and/or infrequent professional supervision. This thesis critiques the theories of perceived organisational support theory, social exchange theory and job characteristics theory, and uses the concept of ‘professional career’, to help analyse the retention of social workers in child protection and welfare