The purpose of this study was to investigate longitudinally, by cephalometric means, alterations in craniocervical morphology and hyoid bone position in adult males and females, in three different age groups at 10-year intervals, and to compare the changes between the two genders. The material consisted of three series of cephalograms of 26 males and 24 females with approximately a 10-year interval between each series. Alterations with increasing age in males and females included: 1 An increase in anterior and posterior facial height in both genders, a reduction in mandibular prognathism, and an increase in the mandibular plane angle in females only. 2 The hyoid bone assumed a more inferior position in relation to different skeletal structures for both sexes. 3 Head posture alterations were similar for the male and female group over time. The overall significant inter-sex changes over a 20-year period were a reduction in mandibular prognathism, an increase in the mandibular plane angle in females, and a more inferior position of the hyoid bone in males.