Background: Patients' negative illness perceptions and beliefs about cardiac rehabilitation (CR) can influence uptake and adherence to CR. Little is known about the interpartner influence of these antecedent variables on quality of life of patients with coronary artery disease (CAD) and their family caregivers. The aims of the study were: 1) to assess differences in illness perceptions, beliefs about CR and quality of life between patients with CAD and their family caregivers upon entry to a CR programme and at 6 months follow-up; and 2) to examine whether patients' and caregivers' perceptions of the patient's illness and beliefs about CR at baseline predict their own and their partner's quality of life at 6 months. Methods: In this longitudinal study of 40 patient-caregiver dyads from one CR service, patients completed the Brief Illness Perception Questionnaire and Beliefs about Cardiac Rehabilitation Questionnaire at baseline and 6 months; and caregivers completed these questionnaires based on their views about the patient's illness and CR. The Short-Form 12 Health Survey was used to assess patients' and caregivers' perceived health status. Dyadic data were analysed using the Actor-Partner Interdependence Model. Results: Most patients (70%) were men, mean age 62.45 years; and most caregivers (70%) were women, mean age 59.55 years. Caregivers were more concerned about the patient's illness than the patients themselves; although they had similar scores for beliefs about CR. Patients had poorer physical health than caregivers, but their level of mental health was similar. Caregivers' poorer mental health at 6 months was predicted by the patient's perceptions of timeline and illness concern (i.e. partner effects). Patient's and caregiver's illness perceptions and beliefs about CR were associated with their own physical and mental health at 6 months (i.e. actor effects). Conclusions: Overall, the patients and caregivers had similar scores for illness perceptions and beliefs about CR. The actor and partner effect results indicate a need to focus on specific illness perceptions and beliefs about CR, targeting both the individual and the dyad, early in the rehabilitation process to help improve patients and caregivers physical and mental health (outcomes).