Xerostomia is a major complaint of many elderly individuals, and although they seek medical help, it usually provides no adequate relief. This complaint is considered a major clinical problem, since not less than 25% to 50%-60% of the population over the age of 65 complain of xerostomia. By definition, Xerostomia is a subjective feeling and in up to one-third of the cases does not reflect a real reduction in salivary flow rate but rather the subjective feeling of a dry mouth. Moreover, only a minute portion of the patients suffer from xerostomia with a known aetiology such as radiotherapy or Sjögren's syndrome, while in the majority of the cases, the aetiology is assumed to be related to age, disease, various medications and drugs or is simply idiopathic. The current review focuses on age-related histological, sialometrical and sialochemical changes and on the possible mechanisms which underlie these changes. Finally, directions for further exploring the subject are suggested.