A longitudinal electromyographic study of the swallowing activity of the anterior temporal and masseter muscles was performed on 21 subjects with complete dentures. In six patients, the lip activity was recorded. At the pretreatment stage, when the patients had a residual anterior dentition, the peak mean voltages of the elevators showed low values (range 18 to 30 uV), and after denture placement, the anterior temporal muscles showed a further decrease. After denture relining, slight increases in temporal activity were noted at the 1-year stage. During the second year, when no corrections of the dentures were made, the temporal activity decreased below the pretreatment level. The masseter activity showed no significant changes during the 2-year observation period. The mandibular lip showed significantly stronger swallowing activity than the maxillary lip. The mean durations of the swallows were markedly longer than values reported for subjects with a complete natural dentition.