Our research was carried out on lateral cephalometric films, maxillary casts and hand-wrist films of 40 patients whose maxillary permanent teeth including the first molars of both sides were existing. These patients, 10 girls and 10 boys at prepubertal stage, and 10 girls and 10 boys at postpubertal stage, neither had an orthodontic treatment nor an adenoidectomy or tonsillectomy operation before. During our studies, hypertrophic tonsils, adenoids and other conditions which would have hindered the nasal respiration had not been detected. Naso-oropharyngeal area and palatal vault depth were measured on the lateral cephalometric films. Again, on the study casts measurements including the volume and depth of the palatal vault, as well as the width of the arch and length of the arch were taken. Comparisons between age groups and sexes were made by evaluating these measurements statistically with paired t-test. Using correlation analysis the relations between these factors were also investigated. Consequently our findings were evaluated in the light of recent publications in the literature.