We made myocardial gammagraphies on a group of 141 patients with acute thoracic pain, using 99 mtc diphosphonates. We obtained images with three projections (LOA, LL and PA); for reading the gammagraphy we used the diagnostic criteria of Berman and Cols. Studying 106 patients with acute myocardial infarction we found affirmative diagnosis in 89 cases (83.93%). In another group, 32 patients with chest angina, the results were negative in 20 cases (62.5%). We got a total of eight false positive images in patients showing post-infarction aneurism, post-defibrillation damage, and myocardial metastatic tumors. This method showed a specificity of 62.9%. Correlation with the electrocardiogram refering to the localization of the infarction, was of 85.39%. This method proved to be of high sensibility and specificity in confirming the diagnosis of acute myocardial infarction or establishing it with certainty in some patients when the electrocardiogram fails and, in some cases, to find out about the evolution and prognostic of the acute myocardial infarction.