Background: Within the integrated community case management of childhood illnesses (iCCM) programme, the traditional health promotion and prevention role of community health workers (CHWs) has been expanded to treatment. Understanding both the impact and the implementation experience of this expanded role are important. In evaluating UNICEF's implementation of iCCM, this qualitative case study explores the implementation experience in Ghana. Methods and Findings: Data were collected through a rapid appraisal using focus groups and individual interviews during a field visit in May 2013 to Accra and the Northern Region of Ghana. We sought to understand the experience of iCCM from the perspective of locally based UNICEF staff, their partners, researchers, Ghana health services management staff, CHWs and their supervisors, nurses in health facilities and mothers receiving the service. Our analysis of the findings showed that there is an appreciation both by mothers and by facility level staff for the contribution of CHWs. Appreciation was expressed for the localisation of the treatment of childhood illness, thus saving mothers from the effort and expense of having to seek treatment outside of the village. Despite an overall expression of value for the expanded role of CHWs, we also found that there were problems in supporting and sustaining their efforts. The data showed concern around CHWs being unpaid, poorly supervised, regularly out of stock, lacking in essential equipment and remaining outside the formal health system. Conclusions: Expanding the roles of CHWs is important and can be valuable, but contextual and health system factors threaten the sustainability of iCCM in Ghana. In this and other implementation sites, policymakers and key donors need to take into account historical lessons from the CHWliterature, while exploring innovative and sustainable mechanisms to secure the programme as part of a government owned and government led strategy.