Angle of mouth opening provides information concerning temporomandibular joint mobility. The aim of this study was to compare angle of mouth opening of dentate and edentuluous subjects at similar ages. Eighty (80) subjects, 24 women and 16 men (mean age 51.2 yrs.) for the dentate group and 21 women and 19 men (mean age 52.3 yrs.) for the edentuluous group participated in the study. The angle of mouth opening measurements were performed with a mandibular goniometer at four independent sessions of three measurements. The angle of mouth opening values of the dentate group were significantly higher than that of the edentulous group. The results of this study revealed that tooth loss resulted in a decrease in angle of mouth opening values independent of gender and age. The clinical implications of this finding is that oral function might well be preserved with advancing age if dentition is maintained in good condition.