This paper discusses a variety of considerations associated with the clinical identification of root caries. While focusing upon this clinical identification process from the perspective of the clinical researcher, the differing diagnostic needs between the clinical researcher and the dental practitioner are frequently addressed. The topic of the identification of untreated root caries lesions includes a presentation of both existing definitions and a proposed set of diagnostic criteria. The presentation of the topic on the identification of arrested and treated root caries lesions emphasizes the diagnostic challenge that will occur due to the newly introduced chemotherapeutic treatments that have been proposed for the control of root caries. The influence of varying examination conditions, techniques and instruments on the reliability and validity of the clinical identification of root caries are also considered. Finally, a preliminary set of clinical research diagnostic conventions, which would both aid the researcher in “grey zone decisions” and enhance comparability of findings across studies, are propo