Background Electroconvulsive therapy (ECT) combined with mood stabilizers is an effective method of treatment for manic episodes; however, there are controversial views on its side effects. Case presentation A 53-year-old man was diagnosed with bipolar disorder during a manic episode, and had previous conditions such as hypertension, and diabetes. He developed reversible delirium and anomic aphasia during combined treatment with lithium and ECT (Li-ECT). No other neurological symptoms or signs happened during the one-month follow-up period. Conclusions The anomic aphasia appeared after ECT was reversible. Li-ECT should be administered with caution to middle- and older-aged patients with comorbidities, and serum Li levels should be closely monitored during the treatment period.