Background: Only 20-40% of candidates actually attend cardiac rehabilitation programs in Australia, with attendance numbers remaining unchanged in the last 20 years. Common barriers to cardiac rehabilitation are geographical isolation, work responsibilities and transportation. Web-based cardiac rehabilitation can provide an alternative, patient centred, flexible delivery option. Objective: The objective of this study was to describe how patient-generated input, through a workshop on desired content and features, informs technology and implementation specifications for the patient portal of a cardiac rehabilitation website. Methods: UX Design theoretical framework, using a co-design workshop, with thematic analysis and a survey. Results: We recruited 7 participants and 1 cardiac rehabilitation coordinator. The median age of participants was 75.0 (IQR 74.0-78.0), 4 (57.1%) were male and all had completed a cardiac rehabilitation program. Most used a smart phone (5, 71.4%) and Facebook (6, 85.7%). Four themes were identified: input information, format of information, usability and support of health behavior change, informing the next iteration of the workshops and contribute to the cardiac rehabilitation patient website development.