ObjectivesElectroconvulsive therapy (ECT) is effective in treating late‐life depression. There is limited research on suicidal behavior and all‐cause mortality in the oldest old after ECT.MethodsOlder adults aged 75 years and above who had been inpatients for moderate to severe depression between January 1, 2011, and December 31, 2017, were included in the study. We used exact and propensity score matching to balance groups. We compared suicidal behavior (fatal and non‐fatal) and all‐cause mortality in those who had received ECT and those with other depression treatments.ResultsOf the study population, 1802 persons who received ECT were matched to 4457 persons with other treatments. There were no significant differences in the risk of suicidal behavior between groups, (within 3 months: odds ratio 0.73; 95% confidence intervals (CI), 0.44–1.23, within 4 months to 1 year: aOR 1.34; 95% CI, 0.84–2.13). All‐cause mortality was lower among ECT recipients compared to those who had received other treatments, both within 3 months (aOR, 0.35; 95% CI, 0.23–0.52), and within 4 months to 1 year (aOR 0.65; 95% CI, 0.50–0.83).ConclusionsCompared to other depression treatments, ECT is not associated with a higher risk of suicidal behavior in patients aged 75 and above. ECT is associated with lower all‐cause mortality in this age group, but we advise caution regarding causal inferences.