We report the case of an 85-year-old man with perfectly controlled hypertension and coronary insufficiency who presented with typical giant cell arteritis (GCA). Thirty-six hours after initiation of prednisolone therapy (1 mg/kg/d), acute coronary insufficiency with non-transmural infarction occurred. Outcome was favorable despite disturbances in heart rhythm. A review of the literature disclosed five cases of myocardial infarction related to GCA, confirmed upon pathological examination. Three out of five myocardial infarctions occurred between the third and seventh treatment days. These findings suggest that corticosteroids may be responsible for coronary complications which arise during the first days of GCA treatment. Furthermore, they justify close monitoring during the initial phase of treatment in patients with coronary diseases.