To evaluate the serum 25 - hydroxyvitamin D concentrations in acute myocardial infarction patients; To evaluate the association between serum 25 - hydroxyvitamin D concentrations and characteristics of acute myocardial infarctionsuch as ST - segment elevationon ECG, left ventricular dyskinesia on echocardiography and the severity of coronary artery lesions. Methods: We employed a case - control study design, including 92 patients diagnosed with acute myocardial infarction and 92 healthy controls.Their demographic, cardiovascular risk factors, and clinical characteristics, investigations were recorded. Serum 25 - hydroxyvitamin D measurement was carried out for all patients. Results: The serum 25 - hydroxyvitamin D concentrations was more deficient in cases than controls; the number of cases was 33 (35.87%) and 0 (0%), respectively. Our study have not found an association between ST - segment on ECG, left ventricular dyskinesia on echocardiography, the severity of coronary artery lesions andconcentration deficiency of serum 25 - hydroxyvitamin D. Conclusion: There was a concentration deficiency of serum 25 - hydroxyvitamin D in acute myocardial infarctionpatients. However, there was no conclusion about the association between ST - segment on ECG, left ventricular dyskinesia on echocardiography, the severity of coronary artery lesions and concentration deficiency of serum 25 - hydroxyvitamin D.