We describe a 76-year-old man with herpes encephalitis whose symptom of severe apathy was improved by the dopamine D2/D3 receptor agonist ropinirole. Brain magnetic resonance imaging had shown lesions in the patient's right mesial temporal cortex, right insula, and bilateral medial frontal regions. During treatment with acyclovir, he had developed severe apathy and depression. On neuropsychological assessment, he scored 21/30 points on the Mini-Mental State Examination, 30/42 on the Starkstein Apathy Scale (cutoff score =16), and 59/80 on the Zung Self-Rating Depression Scale (cutoff score=40). We then started him on ropinirole 0.25 mg/day. Over the next 10 days, his apathy and depression gradually improved. On day 10 of treatment, follow-up testing showed that his Apathy Scale score had improved to 25 points. This case suggests that a low dose of a dopamine receptor agonist may be an effective treatment for patients who develop apathy and depression after encephalitis.