Thirty melancholic patients participated in a double blind trial comparing efficacy of modified bilateral sinewave ECT given twice or thrice weekly. Seizure was monitored on a single channel EEG tracing. All patients received ECTs in the first two weeks of the four week study period. Seizure duration estimate from EEG tracings available for 22 patients (10 patients of thrice weekly group) on all occasions of first two weeks were analysed. Seizure durations significantly reduced through the course in both the groups. Twice weekly ECTs led to significantly less decrements in the seizure duration. This differential reduction was not related to the therapeutic outcome. The improvement in depression in both groups of patients was comparable at the end of two weeks.