Perceptive assessments of the size of objects placed in the mouth were made by manually selecting similar objects from a comparator array, both with and without ocular assistance. Ninety-one young adults made 819 assessments of objects varying only in length. When hands and eyes were used to select an object appearing to be analogous to an intraoral object, subjects made positive errors which were significantly greater than those produced from manual comparisons alone. This confirms the common naive comment that objects feel larger in the mouth than when judged by other means. Peculiarities of the trigeminal system and the oral cavity itself, the bilaterality of the oral stimulation and the perceptive processes, plus certain psychophysical concepts appear to be instrumental in this subjective distortion of size. The intraoral areas utilized by the subjects in their assessments were the same as those normally used for the production of certain consonantal sounds. Sensory information from these sites is important for normal speech, and the testing procedure may be helpful in the investigation of certain speech disorders.