Background: For myocardial infarction survivors, long-term pharmacotherapy is an important element of a complex treatment and a better prognosis may be achieved through better medication adherence. Aim: The purpose of this study is to find out whether it is possible to predict medication adherence of the patients who survived myocardial infarction via assessing their personality. Design and Setting: Analytic cross-sectional study. Methods: The study was held in Hospital of Lithuanian University of Health Sciences Kaunas clinics (HLUHS KK) department of cardiology. Patients with ST-segment elevation myocardial infarction were randomly included and completed questionnaire before discharge from Cardiology unit. We recruited 198 patients with myocardial infarction who completed questionnaire (ICD-10 diagnoses I21.0, I21.1 or I21.2). Medical adherence association with personality was assessed with Morisky-Green medical adherence scale (MMAS-8) and the Big-Five inventory. Results: Medical adherence was associated with conscientiousness, agreeableness, neuroticism and extraversion. There was no significant association with openness to experiences. Neuroticism negatively affected medical adherence. It was determined, that conscientiousness, agreeableness and extraversion positively affected medical adherence. Conclusion: This study demonstrated that good medical adherence in patients with ST-segment elevation myocardial infarction was associated with higher scores in conscientiousness and agreeableness personality traits and lower scores in neuroticism.