OBJECTIVE To correlate existing evaluation tools with clinical information on Duchenne muscular dystrophy (DMD) patients following age and to investigate genetic mutation and its relationship with clinical function. METHODS The medical records of 121 children with DMD who had visited the pediatric rehabilitation clinic from 2006 to 2009 were reviewed. The mean patient age was 9.9±3.4 years and all subjects were male. Collected data included Brooke scale, Vignos scale, bilateral shoulder abductor and knee extensor muscles power, passive range of motion (PROM) of ankle dorsi-flexion, angle of scoliosis, peak cough flow (PCF), fractional shortening (FS), genetic abnormalities, and use of steroid. RESULTS The Brooke and Vignos scales were linearly increased with age (Brooke (y(1)), Vignos (y(2)), age (x), y(1)=0.345x-1.221, R(Brooke) (2)=0.435, y(2)=0.813x-3.079, R(Vignos) (2)=0.558, p<0.001). In relation to the PROM of ankle dorsi-flexion, there was a linear decrease in both ankles (right and left R(2)=0.364, 0.372, p<0.001). Muscle power, Cobb angle, PCF, and FS showed diversity in their degrees, irrespective of age. The genetic test for dystrophin identified exon deletions in 58.0% (69/119), duplications in 9.2% (11/119), and no deletions or duplications in 32.8% (39/119). Statistically, the genetic abnormalities and use of steroid were not definitely associated with functional scale. CONCLUSIONS The Brooke scale, Vignos scale and PROM of ankle dorsi-flexion were partially available to assess DMD patients. However, this study demonstrates the limitations of preexisting scales and clinical parameters incomprehensively reflecting functional changes of DMD patients.