Purpose. The number of teeth in the dentition was compared with the number and types of dental functional units (opposing tooth pairs) to correlate the number of functional units with complaints about chewing and swallowing in the elderly. Material and methods. Complaints of oral-pharyngeal function and food avoidance practices were compared with the number and types of functional units. A convenience sample of 602 elderly subjects (468 men, 134 women, mean age 70 years) were interviewed and examined dentally. Results. Functional unit measures, which included functional arrangement of the teeth and the number and type of teeth present, were found to be more discriminatory and descriptive of masticatory potential than the mere number of teeth. Elderly persons (≥ 60 years of age) with reduced numbers of functional units tended to report difficulty chewing, avoidance of stringy foods (including meat), crunchy foods (including vegetables), and dry solid foods (including breads), and difficulty in swallowing. Removable prostheses did not appear to prevent these consequences and, at least in this elderly population, did not appear to be equivalent to natural teeth in terms of masticatory potential. Conclusions. It is possible that compromised dental function results in the swallowing of poorly chewed food, food avoidance patterns, dietary inadequacies, and systemic changes favoring illness, reduced vigor, debilitation, and shortened life expectancy. Emphasis should be placed on maintaining natural teeth whenever possible. (J Prosthet Dent 1997;77:588-95.).