Medical records of 81 older patients (65 years of age and over) who underwent electroconvulsive therapy (ECT) at a university-affiliated private geriatric hospital were reviewed to evaluate the safety and efficacy of this treatment for depression in the "young-old" (65 to 80 years) compared with the "old-old" age group (over 80 years), a group that has not yet been adequately studied. Information was obtained regarding demographics, medical and psychiatric diagnosis, medications, indications for ECT, number and laterality of treatments, outcome, and complications. Thirty-nine patients 80+ years of age (mean age, 85 +/- 3.2) were compared with 42 patients 65 to 80 years of age (mean age, 74 +/- 5.2). Statistical analysis was performed using confidence intervals of the difference in proportions of patients in each group. There were no significant differences in the demographics, number and laterality of ECT treatments, indications for ECT treatment, medical diagnosis, medications, or prior history of falls, but psychiatric diagnoses differed slightly. Patients over 80 years had significantly more cardiovascular complications and falls (95% confidence interval) and tended to have a worse ASA (American Society of Anesthesiologists) scale rating and a somewhat less successful outcome. This study confirms the role of ECT as a relatively safe and effective treatment, which may be lifesaving in selected depressed older patients. Prospective studies are needed to understand better the long-term outcome and to prevent the morbidity and mortality associated with ECT in this frail, high-risk older group.