Background: Myocardial infarction (MI) is a fatal disease caused by block in the oxygen supply of blood vessels of the heart muscles, leading to permanent heart muscle damage and death of its cells. Aim of work: to assess the relationship between incidence of acute myocardial infarction and its participating factors. Patients and methods: observational, descriptive correlation questionnaire based study on 50 Saudi and non Saudi patients with acute myocardial infarction  who were admitted in cardiac intensive care unit (CICU), medical ward and followed in out-patient department (OPD). They were chosen from King Faisal Medical Center, cardiology department, Taif, Saudi Arabia from the first of March 2016 to the end of April 2016 (2 months duration). Results: Prevalence of MI patients in the 2 months of research was 1.4%. MI was precipitated by a number of factors in Saudi Arabia as old age, increased body mass index, stress, obesity and consumption of high caloric rich diet. Conclusion: The main risk factors of ACS in our patients were hypertension, Stress, obesity; high cholesterol diet and positive family history of cholesterol in addition to old age and smoking. Recommendations:  Combating precipitating factors of MI in Saudi Arabia can decrease the prevalence of the disease