© 2020 Australian Health Promotion Association Issue addressed: Utilisation of professional health care interpreting services improves the quality and safety of health care among patients with limited English proficiency. Health care interpreter service (HCIS) utilisation is inconsistent and suboptimal in Australia. Evidence of the impact of interpreter service use on patient outcomes and costs is limited. This study aimed to identify the proportion of hospitalised patients who received a health care interpreter during admission and describe the characteristics and outcomes for those requiring interpreter services. Methods: A retrospective cohort analysis of linked admitted patient data with internal interpreter audit data. This study included all inpatients in a health district-wide clinical audit of interpreter service use conducted between July 2016 and March 2018. The dataset comprised 74 patients (including 79 unique hospital stays and 90 episodes) from eight hospitals in one regional health district in New South Wales, Australia. Results: Interpreting services were utilised at least once for 54.4% (n = 43) of admissions. Females were more likely to receive an interpreter (65.1% vs 47.1%, P =.04). Age, preferred language, hospital, Diagnosis-Related Group partition and comorbidities were not associated with interpreter service utilisation. Differences in length of stay and cost associated with use of interpreter services were not statistically significant after casemix adjustment. Conclusions: Approximately half of those who required an interpreter received one during their hospital stay. Further investigation is needed to establish whether regular clinical audits contributed to this rate of utilisation, which is higher than reported elsewhere in the literature. So what?: A detailed understanding of regional interpreting service use with evidence from the literature provides compelling and contextual evidence for change, at the level at which the service is delivered. This supports meaningful action to increase utilisation, and improve the quality and safety of health care delivered to patients with limited English proficiency.