The purpose of this study was to evaluate the need for the use of a foot abduction orthosis (FAO) in the treatment of idiopathic clubfeet using the Ponseti technique. Forty-four idiopathic clubfeet were treated with casting using the Ponseti method followed by FAO application. Compliance was defined as full-time FAO use for 3 months and part-time use subsequently. Noncompliance was failure to fulfill the criteria during the first 9 months after casting. Feet were rated according to the Dimeglio and Pirani scoring systems at initial presentation, at the time of FAO application, and at 6 to 9 months of follow-up. At the time of application, no significant differences in scores were found between the groups. At follow-up, the compliant group's scores were significantly (P < 0.01) better than those of the noncompliant group. From the time of application to follow-up, for the compliant group, the Dimeglio scores improved significantly (P = 0.005). For the noncompliant group, the Dimeglio scores deteriorated significantly (P = 0.001). The feet of patients compliant with FAO use remained better corrected than the feet of those patients who were not compliant. Proper use of FAO is essential for successful application of the Ponseti technique.