There is little published evidence regarding the impact of service-user focused interprofessional education in the practice setting. This article reports evaluative case studies of two practice-based interprofessional initiatives, in which service users played a central role. These initiatives formed part of the Trent Universities Interprofessional Learning in Practice (TUILIP) project ( http://tuilip.hwb.shu.ac.uk ), a collaboration between Sheffield Hallam University and the University of Nottingham. Practice settings were an acute mental health service and a community organisation offering care and services to adults with learning disabilities. Interprofessional initiatives were developed by facilitators, and empirically studied at each site. Facilitators, managers, practitioners, students and service users took part in interviews and focus groups to discuss their perceptions of the initiative in their practice setting. The study revealed participants' perceptions of the projects' aims, process and outcomes, factors which facilitated success or proved challenging, and their impact upon individuals, clinical practice and the organisations involved.