Masticatory function can be assessed by chewing tests and questionnaires or personal interviews. Whereas the chewing tests allow the assessment of masticatory efficiency with some objectivity, questionnaires help evaluate a person's subjective responses about chewing ability. Epidemiologic studies indicate a subjective decrease in chewing ability with increasing degree of tooth loss, a trend that was confirmed in the literature. Of interest was that the subjective measures of masticatory ability are often overrated when compared with the functional tests. Masticatory function is a patient factor rather than a parameter that prosthetic treatment can qualify. It depends on a variety of personal and subjective factors that can hardly be influenced by the practitioner. This article describes and discusses scientific sociophysiologic and biomedical approaches to evaluating masticatory function.