Quality of life is a multi-dimensional concept reflecting various aspects of human activity. The aim of the study was to analyse an effect of selected socio-demographic and medical factors on the quality of life of patients after myocardial infarction. The study group consisted of 80 people, aged from 41 to 85, treated for myocardial infarction in medical entities in Mława (Poland) in the first half of 2014. The study used the SF-36v2 questionnaire. In analysis of the quality of life, the value of the mean domain of physical health was 52.6 ±11.35, whereas in the domain of mental health, it was substantially lower, i.e. 37.6 ±5.60. It was found that sex (p = 0.03), age (p = 0.0006), education (p = 0.003), recognized disability (p = 0.0001), and support from the family and friends (p = 0.01) have a significant effect on the quality of life in the physical domain. Such variables as: age (p = 0.006), education (p = 0.03), duration of illness (p = 0.03), undergoing check-ups (p = 0.001), blood pressure control (p = 0.00001), received support from the family and friends (p = 0.0005) significantly determine the level of the quality of life with respect to mental health. A lower quality of patients’ life is observed in the psychological domain than in the physical one.