Objective The aim of this study was to determine whether there has been a measurable change in the dependency and complexity of patients admitted to in-patient rehabilitation in Australia between 2007 and 2016. Methods A retrospective cohort study design was used to examine in-patient rehabilitation data held in the Australasian Rehabilitation Outcomes Centre Registry Database for the period 2007-16. Epidemiological descriptive analysis was used to examine datasets for difference between four discrete years (2007, 2010, 2013 and 2016). Datasets included patient demographics, length of stay (LOS), comorbidities, complications and the Functional Independence Measure (FIM™). Results Between 2007 and 2016, rehabilitation in-patients as a whole: (1) had a mean decrease in total admission FIM score; (2) became more complex, as evidenced by the increased proportion of particular comorbidities impacting on rehabilitation, namely cardiac and respiratory disease, dementia, diabetes and morbid obesity; and (3) had a mean decrease in total discharge FIM score. However, there was an increase in the proportion of patients discharged home from rehabilitation (from 86.5% to 92%) and decreases in onset and rehabilitation LOS of 2.2 and 2.5 days respectively. Conclusion The dependency and complexity of patients admitted to in-patient rehabilitation in Australia has increased between 2007 and 2016. What is known about the topic? Anecdotal reports suggest that rehabilitation patients in Australia have become more complex, necessitating increased active management of their presenting health condition and comorbid health conditions. However, to date, no systematic investigation has been undertaken to examine trends in rehabilitation in-patient dependency and complexity over time. What does this paper add? This study provides measurable evidence of increased dependency and complexity in patients admitted to rehabilitation in Australia. Further, compared with 2007, rehabilitation in-patients as a whole had an increased burden of care on discharge from rehabilitation in 2016. What are the implications for practitioners? The changes in patient dependency and complexity reported in this study have implications for rehabilitation service delivery. This is because the increased need for illness or injury and comorbidity management may result in increased potential for acute complications and health deterioration, and compensatory care for patients during rehabilitation. Clinicians may need to widen their skill set to include more acute and chronic illness management.