Objectives: Electroconvulsive therapy (ECT) is the most effective treatment for depression; however, consensus on predictors for ECT outcome is lacking. We aim to examine the relation between pre-ECT salivary cortisol values and clinical characteristics and ECT outcome in depressed, older persons. Methods: A total of 102 inpatients meeting DSM-IV criteria for depression and referred for ECT were selected. Salivary cortisol was assessed at five time points during the day, providing insight into the cortisol awakening curve to the ground (AUCg) and to the increase (AUCi) and evening cortisol level. Depression severity was assessed using the Montgomery–Asberg Depression Rating Scale (MADRS). Remission was defined as MADRS <10; response was defined as MADRS-reduction of at least 50%. Regression analysis was used to assess associations between cortisol and (1) clinical variables, including depression severity, psychomotor symptoms and presence of psychosis, and (2) ECT outcome. Results: No significant relations were found between AUCg, AUCi, evening cortisol and depression severity, psychomotor symptoms, and presence of psychosis. In addition, no significant relation was found between cortisol and response or remission. Conclusions: Our results do not support a relation between cortisol values and depression characteristics, or ECT outcome in severely depressed, older patients treated with ECT.