OBJECTIVE: To compare the effects of propofol and etomidate on the stimulus variables and efficacy of electroconvulsive therapy (ECT) in depressed inpatients. METHOD: This retrospective study included 54 inpatients (aged 18-75 years) who met the DSM-IV criteria for major depression and were treated with bilateral ECT. For the first part of the study, the primary outcome was the mean stimulus charge per ECT session. For the second part, the main outcome measure was the proportion of patients achieving full remission. RESULTS: Propofol-treated patients showed a higher mean stimulus charge (etomidate 227.58 ± 130.44, propofol 544.91 ± 237.56, p<0.001) despite the lack of a significant difference in starting threshold doses. The propofol group had a shorter mean electroencephalogram (etomidate 69.41 ± 22.50, propofol 42.95 ± 22.26, p<0.001) and motor (etomidate 46.11 ± 14.38, propofol 22.89 ± 7.13, p<0.001) seizure duration and a higher mean number of inadequate seizures (etomidate 0.12 ± 0.15, propofol 0.47 ± 0.26), p<0.001). No significant differences were found between the groups for the effects of the anesthetics on the efficacy of ECT. LIMITATIONS: Our study is limited by a retrospective design and the small number of patients treated with propofol restricted the sample size. CONCLUSIONS: Anesthesia with propofol has a significant reducing effect on seizure duration during the course of ECT which results in more inadequate seizures, despite the use of a higher mean stimulus charge. Regarding the possible effect of the anesthetics on ECT, randomized clinical trials with sufficient power to detect differences is warranted.