Background: Family carers provide significant support to people with a mental illness; yet may experience poor mental and physical health themselves. Among limited research addressing the physical health of carers, studies of carers of people with dementia and young people with psychosis suggest increased risk of chronic diseases in conjunction with higher levels of potentially modifiable lifestyle risk behaviours. This exploratory study, conducted with carers of people with various mental illnesses, aimed to determine: carer prevalence of health risk behaviours (inadequate fruit and vegetable consumption, inadequate physical activity, harmful alcohol consumption, and tobacco smoking); interest in changing 'at risk' behaviours; and potential associations of socio-demographic characteristics with risk status and interest in change. Methods: A cross-sectional survey was conducted among family carers of people with a mental illness (N = 144) residing in New South Wales, Australia. Analyses explored risk behaviour prevalence and interest in change, and associations with socio-demographic variables. Results: Inadequate fruit and vegetable consumption was most prevalent (74.8%), followed by engaging in inadequate amounts of physical activity (57.6%); harmful alcohol consumption (36.3%) and smoking (11.8%). The majority of carers were interested in improving 'at risk' behaviours (56.3-89.2%), with the exception of alcohol consumption (41.5%). Previously or never married participants were more likely to consume inadequate amounts of fruits and/or vegetables compared to those married or cohabiting (Odds Ratio [OR]: 4.1, 95% Confidence Interval [CI]: 1.3-12.9, p =.02). Carers in the workforce were more likely to be engaging in inadequate physical activity (OR: 2.6, 95% CI: 1.2-5.7, p =.02); and male participants were more likely to engage in harmful alcohol consumption (OR: 2.9, 95% CI: 1.1-7.9, p =.03). Working carers were approximately five times more likely to report interest in improving their alcohol consumption (OR: 5.1, 95% CI: 1.3-20.5, p =.02) compared to those not currently in the workforce. Conclusions: Results suggest high engagement in health risk behaviours among carers of people with a mental illness, particularly with regards to harmful alcohol consumption. Findings suggest a need to develop and implement chronic disease prevention strategies. Further research with larger representative samples is needed to confirm findings.