Interventions for Cardiovascular Disease (CVD) risk behaviours among people with severe mental disorders (SMD) are rare and often focus on only one risk behaviour. This project addresses the inequities in cardiac health between the general community and those with SMD. In this study, we will evaluate a low-intensity telephone-delivered health behaviour intervention, with potentially broad reach into the mental health client population. Building upon our existing novel research in which we have evaluated an intervention to modify multiple CVD risk behaviours among smokers with SMD, we will evaluate the efficacy of a Low-Intensity TElephone-delivered intervention (Healthy Lifestyles LITE) that focuses on five specific CVD risk behaviours: smoking, high-saturated-fat diet, low-fibre diet, physical inactivity, and high level of alcohol consumption. The two primary outcomes will be an overall healthy lifestyle behaviour score (a pooled z-score reflecting the five specific CVD risk behaviours which are the basis of eligibility for entrance into the study) and C-reactive protein (CRP), a biomedical marker of CVD risk.