Ageing, like all physiological effects, has a multifactorial origin and is linked to the progressive reduction in the function of some organs and systems. Feeding can play an important role in the control of the ageing process by the improvement of quality of life and the prevention of some pathologies associated with age (renal diseases, obesity, rheumatism, dental pathologies, cardiovascular disorders). Clinical nutrition of old dogs allows us to clarify the animals' nutritional requirements, the required balance of nutrients, the quality of ingredients and dietetic function of some substances. Twenty commercial dry foods formulated for old dogs were analysed. A wide variability of chemical composition was observed among the samples. Very different values were found for size and hardness of kibbles (parameters correlated with the incidence of some dental diseases). Good availability of foods with different nutritional characteristics could be useful to the needs of geriatric dogs. Similarly, a balanced home-made ration could satisfy the specific requirements of old dogs and gratify their owners. In conclusion, a diet for ageing dogs should be "personalized", considering both the nutritional and extra-nutritional factors, which contribute to guarantee optimal well-being and health.