Background <p>Taking into account the significant role of weight disorders and various preventive measures in maintaining human health, as well as the ever-increasing importance of assessing quality of life during the therapeutic process, an interesting research area seems to be analyses comparing selected diagnostic parameters among patients with weight disorders and coronary artery disease, as well as examining the quality of life of patients depending on the preventive measures taken to inhibit disease progression. The aim of the study was to analyze selected clinical parameters of cardiology patients with increased body weight, as well as their health-promoting behaviors and quality of life in relation to body mass indexes.</p> Methods <p>After obtaining informed consent, 293 (100%) patients were enrolled in the study, stratified by the presence of excess body weight and coronary artery disease. A proprietary questionnaire was used to assess quality of life and health-promoting behaviours. It consisted of general and standardized questions: a short version of the WHO Quality of Life questionnaire and the Health Behaviour Inventory. Statistical significance was set at <i>p</i> &lt; 0.05.</p> Results <p>Over 70% (214; 73.04%) of the study group were men, and over 60% (182; 62.12%) were aged 60 to 75. Over half of the study participants (155; 52.90%) were diagnosed with chronic coronary syndrome. The Kruskal-Wallis test showed that patients with an abnormal body mass index (BMI) and coronary artery disease differed significantly from patients with a correct body mass index and coronary artery disease, taking into account the number of points obtained in the Health behaviour Inventory for health practices. Multiple regression analysis showed that the strongest predictor of the dependent variable was the environmental domain (<i>p</i> &lt; 0.001), and a significant, positive effect was also noted for the psychological domain (<i>p</i> = 0.001) and the general health behavior index (<i>p</i> = 0.007). Positive coefficient values confirm that improvement in these areas directly translates into an increase in patients’ subjective quality of life.</p> Conclusions <p>The psychological and environmental resources of the cardiac patients with weight disorders are key determinants of their well-being, while clinical, somatic, and demographic parameters do not directly impact quality of life. There is a perceived need to shift the emphasis in the care of patients with cardiovascular disorders and increased body weight from a biomedical model to a biopsychosocial approach, with the need to implement systematic educational activities promoting healthy behaviors that can contribute not only to a direct improvement in their quality of life but also to its extension and better control of already diagnosed diseases.</p>