en Original Article <strong>Background:</strong> Identify factors affecting medication adherence is effective in the planning of patient care, education and follow-up of heart failure patients. This study aimed to investigate the correlation between type D personality and medication adherence in patients with systolic heart failure was performed.<br> <strong>Methods:</strong> This was a descriptive -correlational study . 100 patients with systolic heart failure at least one year experience of developing heart failure and ejection fraction below 40%&nbsp; admitted to hospital Alborz Social Security of Karaj and the Social Security Hospital of Shahriar in 2013&nbsp; using convenience sampling were entered into the study. Demographic data and type-D personality questionnaire, medication adherence scale in patients with heart failure, was completed by interview. Data was analyzed by SPSS software version 18 and using descriptive statistics and coefficient Pearson correlation.<br> <strong>Results:</strong> 75% of total systolic heart failure patients had type D personality. The %65 of total patients was poor medical adherence. There was a significant negative moderate correlation between Type D personality and medical adherence (p<0.001).<br> <strong>Conclusion:</strong> Patients with systolic heart failure with type D personality had lower drug adherence. Screening of type D personality in patients with heart failure and referral for counseling and appropriate treatment can help to enhance medication adherence of heart failure patients. Systolic heart failure, Medication adherence, Type D personality. 57 64 http://nmj.goums.ac.ir/browse.php?a_code=A-10-33-21&slc_lang=en&sid=1 Sharareh Zeighami Mohammadi Zeighami Mohammadi zeighami@kiau.ac.ir 10031947532846004241 10031947532846004241 Yes Department of Nursing, Karaj Branch, Islamic Azad University, Alborz, Iran Parvin Farmani 10031947532846004242 10031947532846004242 No Social security Alborz hospital, Karaj, Iran.‎ Esmat Danesh 10031947532846004243 10031947532846004243 No Department of clinical psychology, Karaj Branch, Islamic Azad University, Alborz, Iran.