The effects of halotan, isofluran and enfluran on QTc interval were determined in 30 pa¬tients at the early postoperatif period and in 10 control subjects. Famodin, diazepam and pentotal were administered as premedication and induction before norcuran then breat¬hed (%0.8-l volum) halothan (group-I), izofluran (group II) and enfluran (group-Ill), in a mixtur of N204 (4 lt/min.) in02 (2 lt/min.) EKG of patients was recorded with holter mo¬nitoring system at early postoperatif period. QTc interval was found 0.41+0.0194, 0.44+0.0336, 0.44+0.0244, 0.397±0.0183 in group I, group-II. group-Ill, control group respectively. QTc significantly prologed with izofluran (P