This paper will provide an overview of the specific issues related to involving service users and carers in work-based practice assessment of health and social care students. The outcomes of a shared workshop that involved service users and carers, practice assessors and students in the development of an interprofessional assessment tool, will be discussed. Key areas of concern, across all participants, were related to ethical, reliability and validity issues. These will be explored against the background of current literature, and recommendations will be made for involving service users and carers in assessment of practice. The original work for this paper was part of the Assessment and Learning in Practice Settings (ALPS) Centre for Excellence in Teaching and Learning (CETL), which is working towards a framework of interprofessional assessment of common competences in the health and social care professions. (Contains 1 figure.)