Lithium overdoses causing cardiotoxicity are uncommon and electrocardiographic changes suggesting myocardial ischemia are rare. However, some authors have specifically reported the occurrence of ischemic electrocardiography changes due to a lithium overdose. This paper describes a case where electrocardiography changes mimic inferior myocardial infarction during the course of chronic lithium treatment in an elderly patient. The patient's electrocardiography changes were partially resolved after hemodialysis.