Ehlers-Danlos syndrome is an inherited connective tissue disorder. Clinical manifestations of this syndrome are due to fragile connective tissue. Though many cardiovascular disorders in association with it have been reported, myocardial infarction is quite rare. In this report, two cases with type 4 Ehlers-Danlos syndrome and myocardial infarction are described. Patient 1 was a 30-year-old woman. She was diagnosed as having myocardial infarction on the basis of typical changes in electrocardiograms and serum enzymes (CPK, SGOT and LDH). The diagnosis of type 4 Ehlers-Danlos syndrome was made by the microscopic examination of her connective tissue. Patient 2 was a 32-year-old man. He was also diagnosed as having acute myocardial infarction. His fibroblasts were cultured and they could not synthesize type 3 collagen. Type 4 Ehlers-Danlos syndrome was diagnosed. It was likely that myocardial infarction might have resulted from the fragility of their coronary arteries in type 4 Ehlers-Danlos syndrome.