The use of electroconvulsive therapy (ECT) in the US continues to expand in the treatment of psychiatric disorders. Electroconvulsive therapy remains the "gold standard" for the treatment of major depression and a variety of other psychiatric and neurologic disorders. Because of the effectiveness and resurgence of ECT, more patients are considered good candidates for this treatment option. Overall, these patients are medication refractory and elderly, and thus more sensitive to polypharmacy. Additionally, these patients tend to have more coexisting medical problems, and often require that a practitioner have solid clinical knowledge of the fields of medicine and psychiatry. This article will review some of the most common comorbid conditions found in patients referred for ECT.