Fifty-one 6 to 19 year old female patients with unilateral cleft lip and palate were examined to determine the orthodontic treatment frequency and treatment costs during their orthodontic treatment, in anticipation of a coming comprehensive assessment based on Diagnosis Procedure Combination (DPC). The results showed treatment frequencies of 2.5 to 9 times per year, and the orthodontic cost per year was from 9,520 yen (98 US dollars) to 122,328 yen (1,253 US dollars).