Purpose: Circumference of the chest and waist can be one of clinical indicator to reflect respiratory function in children with cerebral palsy. In this study, we compared to differences in the chest/waist circumference and maximal phonation time between children with spastic diplegia and hemiplegia. Methods: Seventeen children with spastic diplegic and hemiplegic cerebral palsy were recruited, who were matched to gender, age, height, weight, and body mass index for control of the known factors affected to respiratory function. The chest/waist circumference and were measured in each group, when children took a breath at rest and at maximal voluntary inspiration/expiration. Results: No significant differences were found in the chest and waist circumference and expansion between the two groups. However, only in the waist expansion, children with diplegic CP were significantly lower extensibility of lung, compared to the other group. In comparison of the maximal phonation time, a significant lower score was shown in children with spastic diplegic CP, compared to children with hemiplegic CP. Conclusion: Our results indicated that children with spastic diplegic CP had smaller chest wall and waist, compared to children with spastic hemiplegic CP. In addition, they showed a shorter time for sustaining phonation than spastic hemiplegic CP did. Therefore, spastic diplegic CP will be required for careful monitor regarding respiratory function in rehabilitation settings.