The purpose of this study was to investigate factors influencing on the early treatment of children with developmental disability. Data was collected from 102 mothers of children with developmental disability who were treated at 4 rehabilitation facilities in Kyunggi-Do and Kangwon-Do. The results were as follows: 1) Of a total of 102, 63 children began to receive rehabilitation therapy during the period 0~12 months (early treatment group), 38 children after 1 year of age (delayed early treatment group). 2) There were statistically significant differences between the early treatment group and delayed early treatment group for prematurity, low birth weight, the time to discover developmental abnormalities, the time of first diagnosis, and first treatment (p<0.05). 3) There were no statistically significant differences in the two groups for level of education, economic status, risk factors (except prematurity and birth weight), home care, family's cooperation and commuting time (p>0.05). Based on this study, the important factors for early treatment were early detection, early diagnosis and constant follow-up for high-risk babies.