Background and Objectives: Stress and stressful situations can be a prelude to fatal diseases such as cardiovascular diseases and hypertension. The aim of this study was to investigate the relationship between perceived stress with five major characteristics of the heart disease in patients with myocardial infarction. Materials and Methods: In this cross sectional descriptive-analytical study that was conducted from May 2005 till October 2009, a total of 3,200 patients with myocardial infarction, from cardiovascular care unit of Gha'em and Imam Reza hospital, Mashhad, were randomly selected. A demographic questionnaire, an instrument for recording laboratory and electrocardiograph finding, and the Perceived Stress Scale were used for data collection. Results: The results of this study show that while 35% of all cases suffer from moderate stress, 65% percent of them suffer from high level of stress. The level of perceived stress in different categories of variables such as gender, educational level, hypertension, history of hypertension, depression, cigarette smoking, exercising, job, level of incoming, location of living, and family history of cardiovascular disease was significantly different from each other. Conclusion: Considering the high levels of stress among patients with myocardial infarction, design and implementation of interventions for identifying stressors, as well as their management seem to be crucial.