Cardiac rehabilitation (CR), a programme of education about risk factors, medication, and lifestyle change, is as an essential part of the care of people who have had a heart attack. Despite the benefits of CR, too few people who would benefit from it are using it. Communication tools in widespread use may provide a solution. The proposed research programme involves the development and evaluation of mobile phone intervention to modify lifestyle factors in people with heart disease (exercise, diet, smoking and adherence to medication). A series of projects are proposed to develop specific behaviour change information and support packages to be delivered via mobile phones and undertake pilot work to evaluate their use prior to conducting a larger trial of their effectiveness. This research has the potential to improve delivery of CR and thereby improve outcomes for people with heart disease.