Proper economic evaluation involves comparative analysis of alternative courses of action in terms of both costs and outcome. This is difficult for general anaesthesia as there are few alternatives and measurement of outcome is difficult to define. All that is generally available is a cost description of different anaesthetic techniques. This article outlines the choice of drugs, breathing systems and ventilatory pattern available to the anaesthetist, and compares regional with general anaesthesia. For each technique the cost and advantages/disadvantages are outlined. There is a discussion of some wider issues involved together with their implications: the abandonment of cyclopropane and nitrous oxide; equipment costs and recommendations by the Association of Anaesthetists of Great Britain and Ireland; staffing levels; legal aspects and the increase in day surgery. The limitation of cost-effectiveness analysis of general anaesthesia is outlined.