Background: The primary objective of this study was to assess the feasibility of the Healthy Lifestyles Program (HLP), a novel 12-month complex intervention based in cognitive behavioural therapy and theories of behavioural change, delivered in a community-based setting in Hamilton, Canada. The secondary objective was to explore implementation factors. Methods/ design: A pragmatic pilot randomised controlled trial using quantitative and qualitative evaluation methods. Participants were randomly allocated to either intervention group (n=15) or comparator group (n=15). The intervention group attended weekly group education sessions and met in-person with a healthcare team monthly to create personalized health goals and action plans. The comparator group met with a research assistant every three months to develop health goals and action plans. We assessed feasibility of the program by measuring recruitment, participation and retention rates, missing data, and attendance. All participant-directed and clinical outcome measures were analyzed for between and within group changes using Generalized Estimating Equations (GEE). Content analysis was conducted for qualitative data. Results: We recruited and randomized 30 participants to each group (n=15) within 3 months. Retention rate was 60% (9/15) for the intervention group and 47% (7/15) for the comparator group. Less than 1% of participant-directed and clinical outcomes were missing. Participants attended an average of 29 of 43 educational sessions and 100% of one-to-one sessions. The healthcare team valued the program’s holistic approach to care, increased time and interaction with participants, professional collaboration, and the ability to provide counselling and health supports. Location accessibility was an important factor facilitating implementation. Reducing the number of psycho-social education sessions and having access to a gym could improve retention and delivery of the program. Conclusion: This study has demonstrated the feasibility of the HLP with minor modifications recommended for a larger trial and for the intervention. / Thesis / Master of Public Health (MPH) / Rates of chronic physical and mental health illness are rising in Canada. Lifestyle or behavioural changes can prevent or manage chronic diseases. The aim of this pilot study is to test the feasibility of delivering a 12-month Healthy Lifestyles Program to participants in Hamilton, Canada. The Healthy Lifestyles Program is a complex intervention designed to help participants identify health goals and action plans to achieve those goals with the guidance of healthcare professionals. We observed that the program was successfully delivered, accepted by participants and staff and required minor changes to the study design for a scaled-up study. The program showed positive trends for improving goal attainment, depression, and loneliness scores. The results of this study will help inform the design and scale-up of a larger study.