OBJECTIVE: The importance of coping style factors in the process of emotional adjustment following acquired brain injury (ABI) has been gaining increased attention. To assess ways of coping with distress accurately, clear conceptual definitions and measurement precision is vital. The purpose of this study was to investigate the psychometric properties of a well-known measure of coping, the Coping Inventory for Stressful Situations (CISS), for people who have experienced an ABI; and to modify the CISS, where necessary, to create a more reliable and valid measurement tool for this clinical group. METHODS: Psychometric properties were investigated using Rasch analysis of responses from a sample of adults with ABI (n = 207). The internal consistency reliability and construct validity of the scale were examined. RESULTS: All originally proposed subscales were not valid or reliable and, as such, were incapable of interval-level measurement within this sample - Task: χ(2) (32, N = 207) = 105.1, p < .001; Emotion: χ(2) (32, N = 204) = 121.9, p < .001; Avoidance: χ(2) (32, N = 207) = 66.7, p < .001. Three valid and reliable subscales were derived measuring emotion-, task-, and avoidance-oriented coping styles by removing items that provided the most unreliable information and exploring fit to the Rasch model. CONCLUSIONS: The original version of the CISS may not be a valid and reliable measure of coping style following ABI. Modified subscales of the three distinct coping domains have been proposed that would help to improve measurement of coping style following ABI in future research and clinical practice. PRACTITIONER POINTS: How people cope with difficulties following an ABI has been shown to impact upon emotional outcomes and functional recovery. The original version of the CISS was found to be an imprecise measure of coping following ABI. A modified version of the CISS was found to be a valid and reliable measure of three styles of coping (task-focused, emotion-focused, and avoidance-focused) that conforms to the properties of interval-level measurement as represented by the Rasch model. This structure is in keeping with previous theoretical models of coping. We advise caution about including items (1, 6, 7, 22, 24, 28, 29, 33, 34, and 46) that were found to diverge from the expectations of the Rasch measurement model in total subscale scores for measuring change in coping style. A conversion table for the three modified subscales is included in this paper to convert total raw scores into Rasch transformed logit values. Identifying strengths and weaknesses in coping style could be a means of guiding psychological intervention to promote good recovery following ABI. The sample included mainly people who had experienced non-traumatic brain injuries (e.g., a stroke). This research could be extended to include broader sample of people with differing brain injury aetiologies and neurological disorders.