In the present study, we examined the chewing performance of 70 elderly persons. Self-assessment of chewing problems and clinical classification using the modified Eichner index showed little correlation (Kappa value = 0.28; 95% confidence interval (CI) = 0.05-0.51). The sensitivity and specificity were 0.52 and 0.76, respectively. On the other hand, the mastication score determined by evaluation of a questionnaire on food intake and classification using the modified Eichner index showed high agreement (Kappa value = 0.73; 95% CI = 0.50-0.96). The sensitivity and specificity were 0.76 and 0.95, respectively. The mastication score showed significant correlation with other masticatory functions such as maximum biting force, occlusal contact area and the number of missing teeth (P < 0.01). These results suggest that the use of a questionnaire on food intake would be informative for epidemiological surveys of chewing activity in the elderly.