A number of studies are beginning to show that oral disorders can have a significant impact on the functional, social and psychological well-being of older adults. The Oral Health Impact Profile (OHIP) was developed to collect information on the nature and extent of this impact, and to facilitate the use of such data in oral health surveys, the evaluation of dental procedures and the clinical evaluation of patients. This paper describes OHIP and the results of two studies undertaken in Ontario to assess its measurement properties and to provide preliminary data on the way in which oral conditions compromise the quality of life of older adults. The measure proved to be reliable and valid, while data collected using this measure indicated that oral conditions have a negative impact on the daily lives of substantial proportions of older people. This impact was particularly marked among both edentulous and dentulous individuals who did not make regular visits for dental care.