It has been fifteen years since the Department of Orthodontics started in 1973, and this report concerns mainly the results of clinical observations during these period. The results were as follows: 1) Three thousand four hundred and three patients visited during a fifteen years period and 2,065 (61%) of them received orthodontic treatment. This statistical investigation was performed on 2,065 patients. 2) The numbers of treated patients increased from 1973 to 1983 without 1980 but have almost unchanged with about 180 patients from 1984 to 1987. 3) The male patients were less than the female by the ratio of 1:1.67. As to age, the patients from 6 to 12 years old accounted for 72% of all the treated. 4) Analyzed by dental age categories, patients at the stage of III A and III B comprised 54% of all the treated. 5) Analyzed by month, the patients visited on March, July and August in spring and summer vacations. 6) Most of the patients (92%) lived in Fukuoka Prefecture and 38% of them lived in Sawara-ku, where lay in the south-western part of Fukuoka city. 7) Fifty six per cent of all patients were introduced by doctors and dentists. 8) As to malocclutions, the number of mandibular protrusion was the largest, crowding case was next, and maxillary protrusion was third. The total sum of these three cases accounted for 78% of all the treated. 9) In the initial orthodontic appliances, the use of the multi-brackets appliances was first, the chin cap appliances was second and plate appliances was third. The total sum of these three appliances accounted for about 73%. 10) Analyzing to age and initial orthodontic appliances, plate, chin cap, F. K. O. and I. M. A. appliances were used at the age from 7 to 8. Lingual arch appliances were also used at the age of 8. The multi-brackets appliances increased remarkably during the recent five year period and were used at the age of 10 to 11 and over 20 years.