The clouded leopard (Neofelis nebulosa) has proved to be a difficult animal to breed in captivity because males often kill their prospective mates when they are introduced for breeding purposes. Very little is known about clouded leopard behaviour in the wild as indicated by a literature review of the field studies which have been undertaken. The main purpose of this study was to try to discover a method which might prove successful in introducing adult pairs of clouded leopards to each other without severe injury or death occurring. It was also hoped that by studying the leopards at night, when they were most at ease, that more information might be obtained about the habits of this creature which is secretive and shy in the wild. A series of experimental nightly procedures were designed to give each cat safe access to the other's territory. During these nights the cats could investigate each other's scent and build up a an olfactory familiarity before eventually being introduced for mating. The effect of this procedure on their behaviour was monitored. They were successfully introduced without mishap but did not mate. Part of the study involved an investigation of the clouded leopards’ enclosure utilisation during which an unusual behaviour known as cheekmarking was repeatedly observed. This behaviour and the sites where it took place, were investigated. Samples of skin, procured from dead clouded leopards, revealed the presence of pronounced sebaceous glands in the cheek areas of these cats suggesting the likelihood of a cheekmarking substance. Samples of hair were then analysed using a gas chromatograph in order to identify marking compounds. This work has shown that unfamiliar adult clouded leopards may be eased towards eventual safe introduction using a method of gradual territory overlap which may help reduce the amount of introductory deaths occurring in captivity.