The subject of this paper is critical review of the reported research approaches used when undertaking clinical mentor research in the UK. The term ‘Mentor’ is used to denote a clinical practitioner who is responsible for the teaching, assessing and supervision of student nurses undertaking clinical practice. Imperatives such as new quality assurances in the UK are cited as part of the rationale for conducting the review. In these new initiatives, clinical placements are viewed as an integral feature of Higher Education Institution’s (HEI) nurse education provision. Within these new quality assurance processes, there is an emphasis on the importance of clinical learning environments and the impact that mentors have on student learning. A critical review of 19 reports that have clinical mentors as their target population was undertaken. Factors such as the subject areas of the studies reviewed, research methodologies, sampling issues, responses rates and ethical considerations were the focus of the critical appraisal. It was found that most studies used postal survey approaches. Methodological weaknesses were found to relate to such things as questionnaire design, sampling and poor response rates. It is concluded that the study gives further insights into the debate about the rigor of nursing research and particularly nurse education research and therefore is of interest not only to nurse education researchers but also to nurse researchers generally.