Propofol/alfentanil anaesthesia was compared with thiopentone/halothane anaesthesia in 86 midazolam-atropine premedicated children undergoing minor otolaryngological surgery. The study was randomised, and evaluation of recovery from anaesthesia was double-blind. The children were divided into two age groups: 1-3 years and 4 years and older. Particular attention was paid to ECG changes during anaesthesia and to the rapidity of recovery. One minute after alfentanil 15 micrograms.kg-1, the children in the propofol group received propofol 2.0-3.0 mg.kg-1 followed by propofol infusion 15 mg.kg-1.h-1. In addition, 0.1% suxamethonium 6 mg.kg-1.h-1 was infused during operation. The other children received thiopentone 5-7 mg.kg-1 followed by halothane (0.5-2%) immediately after endotracheal intubation. Junctional rhythm occurred in 5-35% of the children independent of anaesthesia method, and ventricular ectopic beats were seen in 20% of the older children during halothane anaesthesia. Recovery with respect to times to eye opening or response to verbal contact was significantly faster after propofol/alfentanil anaesthesia than after thiopentone/halothane anaesthesia in the older but not in the younger age group. Furthermore, in the younger age group significantly more crying occurred after propofol/alfentanil than after thiopentone/halothane anaesthesia. On the basis of this study, thiopentone/halothane anaesthesia is recommended for children aged 1-3 years and propofol/alfentanil anaesthesia for older children undergoing adenoidectomy and/or tonsillectomy.