Evidence on socioeconomic inequalities in the treatment of coronary heart disease is rare. The aim of this study is to analyse how socioeconomic inequalities impact treatment on the pathway of care for coronary heart disease, and which factors and mechanisms are responsible for socioeconomic inequalities in healthcare. Therefore, a systematic review of the international literature as well as a longitudinal qualitative study have been conducted. The results showed that socioeconomic inequalities are more pronounced on the pathway to diagnosis and in elective treatment of less severe forms of coronary heart disease. Socioeconomic inequalities diminish along the pathway of treatment for coronary heart disease and were found to be weaker in urgent treatment of an acute myocardial infarction. Above all, differences in the patient’s ability to assess their subjective need of utilizing healthcare while interpreting their results might cause inequalities in healthcare, as well as patient’s information level about treatment, their illness perception and perceived role in healthcare.