Minerals are inorganic elements that are considered essential nutrients responsible for different functions in the body and are necessary for the normal functioning of the organism. There are significant interactions among many minerals that can affect the absorption, the metabolism and their role in the body. The study of the mineral deficiency and excess problem in the diet of dogs and cats, from the clinical aspect of their manifestation, is of crucial importance. The disbalance of minerals in a pet's diet will lead to various clinical manifestations that can ultimately lead to death. As a result, the level of most minerals in a pet's diet should be considered in relation to other nutritional ingredients, with the aim of achieving optimal dietary balance. The objective of this thesis is to demonstrate the function and importance of particular minerals in the diet of dogs and cats, what are their required quantities in terms of age and type, with emphasis on the minimum and maximum meal concentrations to be able to unite the clinical manifestations of their disbalance (excess and deficiency) which would, in the end, facilitate the differential diagnosis and indicate to irregularities in feeding. It is necessary to emphasize the extraordinary importance of a balanced diet, with the conscientious inclusion of mineral supplements in the pet food, whether the food is commercially produced or home-made, to avoid nutritional mistakes and clinical manifestations of mineral deficiency and excess.