Some method of assessing self-awareness of deficits in patients with traumatic brain injury (TBI) is required to increase our understanding of the phenomenon, and to then evaluate strategies for clinical intervention with patients who lack such self-awareness. Options for the assessment of self-awareness of deficits following TBI are reviewed. The most commonly used method is comparison of patients' self-ratings on questionnaires of functional abilities with ratings by relatives or staff on the same questionnaires. An additional method of assessment, an interviewer-rated semi-structured interview is proposed (the Self-Awareness of Deficits Interview), and some preliminary inter-rater reliability data are presented. However, quantitative methods of evaluating self-awareness have shortcomings, and qualitative research may be more appropriate in some circumstances. An approach which makes use of multiple measures to evaluate self-awareness of deficits is recommended.