Objective
To investigate the effect of epilepsy and neonatal seizure on development in children with cerebral palsy (CP) or delayed development (DD).

Method
The subjects were 135 patients with CP or DD. Development was evaluated by Bayley Scale of Infant Development II (BSID II). Epilepsy was diagnosed on the base of clinical features, past history and electroencephalography.

Results
The incidence of epilepsy was 18.4% in CP, and 37.8% in DD. Spastic quadriplegia of CP has the highest incidence of epilepsy (38.4%). First seizure attack was occurred before 6 months old of age in 66.7% of CP with epilepsy and in 64.3% of DD with epilepsy. The prevailing type of epilepsy was generalized seizure in DD (57.1%), partial seizure in CP (50.0%). The group with epilepsy had lower psychomotor and mental development quotient on BSID II than the group without epilesy (p＜0.05). Polytherapy was more used to control epilepsy than monotherapy. Valproate (50.0%), phenobarbital (37.5%), carbamazepine (31.3%) were commonly used drugs for controlling epilepsy.

Conclusion
The epilpesy has a negative effect on psychomotor and mental development in the children with CP or DD.