Abstract: A system for animal weight management relates to the technical field of optimising animal weight and therefore health. It can be a problem that domestic animals may become underweight or overweight and it can be difficult to obtain accurate information relating to diet and exercise and so difficult to effectively treat animals. The system comprises a database having animal food information, a food plan section to allow creation of a food plan for an animal, an exercise plan section to allow creation of an exercise plan for the animal, a monitoring section including storage to store information about the weight history of the animal and the animal's activity, and a monitor adapted to be attached to the animal and provide information about the animal's activity to the monitoring section. The system is principally used by animal health professionals and animal caregivers on domestic animals to optimise the weight and therefore health of the animals.