Aim: This study aimed to compare the effects of dexmedetomidine-propofol and ketamine-propofol sedation on haemodynamic stability, immobility, and recovery time in children who underwent transcatheter closure of atrial septal defects. Methods: In all, 46 children scheduled for transcatheter closure of atrial septal defects (n = 46) were included. The dexmedetomidine-propofol group (n = 23) received dexmedetomidine (1 mu g/kg) and propofol (1 mg/kg) for induction, followed by dexmedetomidine (0.5 mu g/kg/hour) and propofol (100 mu g/kg/minute) for maintenance. The ketamine-propofol group (n = 23) received ketamine (1 mg/kg) and propofol (1 mg/kg) for induction, followed by ketamine (1 mg/kg) and propofol (100 mu g/kg/minute) for maintenance. Results: In all, 11 patients in the dexmedetomidine group (47.8%) and one patient (4.3%) in the ketamine group demonstrated a decrease >= 20% from the baseline in mean arterial pressure (p=0.01). Heart rates decreased >= 20% from the baseline value in 10 patients (43.4%) in the dexmedetomidine group and three patients (13%) in the ketamine group (p = 0.047). Heart rate values were observed to be lower in the dexmedetomidine group throughout the procedure after the first 10 minutes. The number of patients requiring additional propofol was higher in the dexmedetomidine group (p = 0.01). The recovery times were similar in the two groups -15.86 +/- 6.50 minutes in the dexmedetomidine group and 19.65 +/- 8.19 minutes in the ketamine group; p = 0.09. Conclusion: The ketamine-propofol combination was less likely to induce haemodynamic instability, with no significant change in recovery times, compared with the dexmedetomidine-propofol combination. The ketamine-propofol combination provided good conditions for the intervention.