The feeding of captive animals is more complex than merely combining compatible feed ingredients and rationing the amounts to what is believed to be adequate. The aim of this project is to reduce the expenses that the zoo is experiencing. The Johannesburg Zoo is home to 2040 animals of which there are 380 different species that all need to be fed on a daily basis. The important aspects which are addressed in this project is firstly determining the animal diets at least possible cost and secondly ensuring that all the diets are as nutritionally balanced as is allowed for given the feed ingredients. A model, capable of determining least cost diets is developed in this project. The model is applied to the 80% of the feed ingredients that contribute primarily to the high expense of feeding animals. The animal diets covered include all: carnivores, omnivores, antelope and pachyderms.