To find an association between smoking and the development of myocardial infarction in male patients above forty years of age presenting at the echocardiology department of Sudan heart center Khartoum. A prospective cohort study was carried out at the echocardiography department of Sudan Heart Center in Khartoum-Sudan between July 2012 and June 2014. The study population comprised a total of 168 adult male patients who underwent cardiac ultrasound scanning. Out of a total of 144 cases, 65% (94) of patients were smokers, 74% of the 94 cases smoked for more than 10 years, and 26% of the 94 cases smoked for less than 10 years. With this study it was concluded that smoking is a risk factor for the development of myocardial infarction. This study showed that patients with myocardial infarction are more likely to have a past history of smoking.