The aim of this study was to evaluate the effect of a ketamine:propofol combination ('ketofol') for electroconvulsive therapy on seizure activity, haemodynamic response and recovery parameters, and to compare with these with the effects of propofol alone. Twenty-four patients underwent a total of 144 electroconvulsive therapy sessions, allocated in this prospective, double-blind, crossover study. Patients were randomly assigned to receive 1 mg/kg ketofol (0.5 mg/kg propofol plus 0.5 mg/kg ketamine) or 1 mg/kg propofol 1% for anaesthesia induction. Seizure duration and quality, haemodynamic data, recovery parameters and side-effects were recorded and analysed between groups. Both motor and electroencephalography seizure durations in the ketofol group (29 +/- 17 and 41 +/- 17 seconds, respectively) were similar to that in the propofol group (28 +/- 13 and 38 +/- 16 seconds, respectively). Postictal suppression index was higher in the ketofol group (89.63 +/- 7.88) than in the propofol group (79.74 +/- 14.6) (P <0.05). In the ketofol group, heart rate after the seizure ended and mean arterial pressures, recorded at 0 and 5 minutes after the seizure ended, were higher than in the propofol group. Time to obeying commands was longer in the ketofol group (P <0.05). There were no untoward psychological reactions following ketofol. Although no superiority to propofol in terms of seizure duration, haemodynamic or recovery parameters was found, the ketofol mixture selected in our study provided better seizure quality than propofol. We conclude that ketofol can be an alternative strategy to enhance the seizure quality and clinical efficiency of electroconvulsive therapy.