Objective: This study aimed to describe family system functioning, in providing care for a family member, after surviving a severe traumatic brain injury (TBI).Material and Methods: A cross sectional survey, using a self-report questionnaire, was conducted with 77 family members; from 32 families, caring for survivors from one province in southern Thailand. Family system functioning was measured using the Family Assessment Measure III (FAM-III) General Scale, Thai version as well as a demographic questionnaire. Descriptive statistics were applied to analyze family functioning including means, standard deviation, percentage and T-scores.Results: The findings showed that the overall family system functioning existed within the moderate level (M=49.94, S.D. =8.99). The finding also indicated moderate levels of functioning within the FAM III subscales.Conclusion: The present findings provide evidence that family systems functioning was at a moderate level in those providing care for a family member who had sustained a severe TBI. This level of function might pose difficulty regarding ability of the family towards a variety of basic, developmental and crisis tasks. The investigation suggests a future study, complementing quantitative methods with qualitative approaches.