Purpose: The author evaluated the clinical and radiological results after wearing the medial arch supports in children. Materials and Methods: 103 patients who had symptomatic flat feet were evaluated from march, 2002 to may 2009. All patients wore the medial arch supports according to the symptoms. We measured parameters at weight-bearing radiographs before and after medial arch support were worn. We also evaluated the clinical scores using the AOFAS score. Results: Mean age of patients was 97 months (11-204 months), all foot of patients involved bilaterally. Mean talo-first metatarsal angle of right foot was $17.7{pm}9.4$ and left foot was $19.96{pm}9.5$ degrees at AP radiograph in pre-wearing state. Mean calcaneal pitch angle of right foot was $12.0{pm}5.3$ and left foot was $11.9{pm}5.8$ degrees at lateral radiograph in pre-wearing state. Mean talo-first metatarsal angle of right foot was $14.4{pm}8.05$ and left foot was $13.1{pm}8.77$ degrees at AP radiograph in post-wearing state. Mean calcaneal pitch angle of right foot was $16.4{pm}5.75$ left foot was $16.5{pm}5.6$ degrees at lateral radiograph in post-wearing state. The radiographic angles between pre-wearing and post-wearing state were statistically significant (p<0.05). Mean pre-wearing AOFAS hindfoot score was $66.7{pm}9.25$, midfoot score was $60.0{pm}9.34$ forefoot score was $57.1{pm}11.8$. Mean post-wearing AOFAS hindfoot score was $73.2{pm}9.73$, midfoot score was $68.1{pm}10.1$, forefoot score was $67.2{pm}11.4$. The forefoot score was highest improving scores among the AOFAS scores. Conclusion: From our study, we concluded that medial arch support was effective for symptomatic flat feet of children in radiological and clinical results from our study.