As part of a C.O.R.E, multi-site longitudinal study comparing continuation electroconvulsive therapy (ECT) vs. continuation pharmacotherapy, the authors determined the response of 253 patients with major depression to acute-phase, bilateral ECT by use of the 24-item Hamilton Rating Scale for Depression, Remission rates for three age-groups, greater than or equal to 65 years; 46-64 years; and less than or equal to 45 years, were 90 percent, 89.8 percent, and 70 percent, respectively, Age, as a continuous variable, positively influenced response to treatment. Bilateral, dose-titrated ECT is a highly effective acute treatment for major depression, and older age confers a greater likelihood of achieving remission.