Cerebral palsy is a disorder with variable nature, distribution and severity of motor dysfunction and the prediction of the eventual outcome of motor function is not easy. This study was carried out to determine the motor developmental age as a percentile and prognosticate the ambulatory ability.

The 354 children with cerebral palsy, ages 3 months to 14 years were included for motor age determination and 48 cerebral palsied children, ages ranging from 7 months to 10 years were re-examined until 10 years old for predicting walking ability related to the sitting age.

The results were as follows;

1) The type distribution was 22.7% of spastic diplegia, 16.2% of spastic quadriplegia, 51.4% of athetoid and 9.7% of mixed type.

2) The 9 stages of motor development were head control, elbow support, roll over, sitting when sat, crawl, sitting alone, pull to stand, walk with support, and walk alone. The age of 10, 50, 75, and 90 percentiles was studied in each stages and compared with each type.

3) The age of 50% of the cerebral palsied children walk alone was 63.6 months in spastic diplegia, 67.2 months in spastic quadriplegia, 84.1 months in athetoid and 93.6 months in mixed type.

4) All children who sat by 2 years became independent ambulators whereas 78% of those sat between 2 and 3 years achieved ambulatory function and only 52% among who sat after 3 years became independent ambulators.