We performed a prospective study to determine whether the walking pattern of children with flatfoot can be influenced by using shoes and custom-modeled insoles. One hundred and thirty-two children (mean age ; 4.20±2.53) who had been referred by a physiatrist, and who were diagnosed with flatfoot at the brace clinic in our institute, were assigned to three groups : The first group was asked to walk barefoot, the second one to walk with shoes without insoles and the last one to walk with shoes with insoles. We measured walking speed, cadence, step length, step width, the duration of right and left stance phases, both double-limb stance phases, both swing phases, walking angle, and toe angle using a 2.4 m sheet-type Gait Analyzer, the Walk Way MW-1000 ^TM, at the individual's self-selected speed. Compared with the barefoot group, a significant increase was observed in the group using shoes with custom-modeled insoles in both walking speed and step length on both sides, and there were reductions in swing phase and walking angle on both sides (paired t-test ; p<0.002).