Few studies exist of using remifentanil and intravenous ketamine for anaesthetic induction in paediatric day case anaesthesia. Therefore, we studied 75 unpremedicated ASA I-II children (age 1-7 years) who were randomly assigned in a double-blind fashion to receive either remifentanil (1 microgram/kg), ketamine (0.7 mg/kg) or placebo before the anaesthetic induction. Anaesthesia was induced with propofol and maintained with O2-N2O-sevoflurane. Induction characteristics, recovery times and the need for postoperative analgesia were evaluated. The required induction dose of propofol was lower in the groups receiving remifentanil and ketamine compared with the group receiving placebo. After tracheal intubation heart rate and blood pressure were better attenuated with remifentanil than with ketamine or placebo. In the recovery room children in the placebo group required more doses of oxycodone than the other two groups but this did not reach statistical significance. There were no differences between the groups in achieving predetermined recovery end-points, attaining full points on the Steward score or in the well being at home. In conclusion, remifentanil provides haemodynamically more stable induction of anaesthesia compared with ketamine or placebo. Ketamine with its' longer duration of action does not prolong recovery but does not have a clear opioid-sparing effect either in the immediate postoperative period.