The relevance of the problem is caused by the prevalence of cardiovascular diseases among the population, including coronary heartdisease which requires surgical treatment, on the one hand, and low ratesof treatment adherence among patients with chronic diseases, which reducethe effectiveness of the treatment and survival rates of patients, on theother hand. Patients after CABG were divided into groups according to thedegree of their adherence to treatment and were examined by using the BigFive Questionnaire. Differences between the groups on the scales“conscientiousness” (p < 0.001), “openness” (p < 0.001), “agreeableness”(p < 0.05), and “neuroticism” (p < 0.05) were revealed. The study showedthat the psychological factors are relevant in the definition of adherence totreatment and patients’ personality traits are potentially significant for theprediction of its degree among patients after CABG.