OBJECTIVES: The present study is the first large-scale, multicenter survey on modified electroconvulsive therapy (ECT) in Japan. We aimed to comprehend the current implementation status of ECT based on the annual reports of 2016 from 21 facilities that were certified by the Japanese Society of General Hospital Psychiatry as ECT certified facilities and participated in this multicenter observational study. METHODS: We investigated the distributions of diagnosis, gender, and age of patients receiving acute-phase ECT, and the efficacy, safety, and adverse events. RESULTS: The number of patients receiving acute-phase ECT was 524. According to International Classification of Diseases, 10th Revision, 344 patients (65.6%) were diagnosed with mood disorders (F3), 156 patients (29.8%) were diagnosed with schizophrenia and with schizotypal and delusional disorders (F2), and 151 subjects were male and 334 subjects were female. The mean age of patients was 60.4 years (SD 15.9), and patients 60 years or older accounted for 57.9%. Efficacy did not significantly differ between diagnoses, nor between genders. However, the efficacy rate was significantly higher in elderly patients. In acute-phase ECT, 4 severe adverse events occurred. CONCLUSIONS: Our multicenter study confirmed that F3 (mood disorders) was the most common indication for ECT at 66%, followed by F2 (schizophrenia, schizotypal, and delusional disorders) at 30%, with no difference in efficacy, indicating that ECT is still performed as 1 of the treatment options for schizophrenia in Japan. The present results suggested that accumulation of annual data from multiple centers can be useful for more effective and safer ECT practices.