Objective: To assess the frequency of hyperhomocysteinemia in patients of first attack of ST-segment elevated myocardialinfarction under age of 40 years. Design: Cross sectional study. Period: December 2009 to June 2010. Setting: Ch. Pervaiz Elahi Institute ofCardiology, Multan. Material and methods: A total of 65 patients of acute myocardial infarction were included in the study on the basis of chestpain, ECG changes and increased cardiac enzyme. Results: A total of 65 patients fulfilled the inclusion criteria were included the study. Meanage was 35.68 years. Out of the 65 patients, 87.7% were male and 12.3% were female, 41.5% patients has increased homocysteine level while68.5% had normal homocysteine level. Conclusions: Plasma Hcy is an important risk factor for the development of the acute myocardialinfarction.