Animal anaesthesia is a wide and varied subject considering the great number of available animal models, each having its characteristic tolerance and reaction to anaesthesia and its behavioural peculiarity. It is more often than not that experimental researchers tend to give scant attention to animal anaesthesia in the preparation of a research protocol as a result of which their research findings can become difficult or impossible to interpret. This article outlines the fundamental anaesthetic requirements and techniques in various animals and the practices adopted by the Department of Experimental Surgery, Singapore General Hospital. Consideration in the choice of anaesthetic drugs in various animal models and experimental situations, and problems of animal handling before and after anaesthesia are highlighted.