The purpose of this prospective study was to examine whether illness acceptance and helplessness predict the subjective health of patients with a cardiac problem over a six months period, after controlling for baseline subjective health. A second aim was to examine whether acceptance and helplessness remain stable over time. One hundred and six cardiac patients participated in the study (66 males and 40 females. Mean age = 59.34 years; SD = 13.22). According to the results, acceptance predicted subjective health (i.e., physical functioning and emotional well-being) in a positive way, whereas helplessness predicted subjective health in a negative way. These effects were both direct and indirect through certain coping strategies (i.e., emotional reactions, wishful thinking and palliative coping). A further important finding was that illness acceptance and helplessness remained stable over time and had an independent impact on subjective health. These findings have significant clinical implications and suggest that interventions with a concurrent focus on illness acceptance and helplessness could promote patients' subjective health.