Delirium is a frequent and serious condition often seen in hospitalized patients, especially the elderly. Treatment of the somatic illness causing the delirium, and antipsychotic medication will usually resolve the condition. Sometimes, however, the condition is refractory towards medical treatment and in this situation electroconvulsive therapy (ECT) can be a quick and efficient treatment. In this case report of a 26-year-old man a post-operative intractable delirium persisting for three weeks was efficiently and swiftly relieved by three consecutive ECTs. The patient was discharged without need for further treatment.