Day-case anaesthesia requires rapidly eliminated anaesthetics which are relatively expensive. This multinational, multicentre European study assessed the relative costs of propofol or sevoflurane anaesthesia in 211 patients. Anaesthesia was induced and maintained with propofol in group 1, with propofol and sevoflurane in group 2, and with sevoflurane in group 3. Drug and delivery costs were calculated in US$. Induction of anaesthesia was fastest in groups 1 and 2, although spontaneous ventilation resumed earliest in group 3. Emergence times and times at which patients were fit for discharge were similar in all groups. Group 2 had the lowest costs based on actual drug use (mean $14.2 (SEM 0.8) vs $18.7 (0.8) and $17.3 (0.8) in groups 1 and 3, respectively). Anaesthetic drug wastage and disposable costs were highest in group 1 and lowest in group 3. Consequently, total costs were highest in group 1 ($31.9 (0.9)) compared with groups 2 ($19.7 (0.9)) and 3 ($18.8 (0.9)). Although we observed increased nausea and vomiting in groups 2 and 3 and reduced patient satisfaction in group 3, these differences should be balanced against the greater cost of propofol anaesthesia.