In this chapter, epilepsy or seizure in special populations or conditions, pregnant women or those who are planning to be pregnant elderly individuals, patients with a systemic disease, and mentally retarded subjects are discussed. Pregnancy in pregnant woman is associated with increased obstetric risks and increased adverse neonatal outcomes. Effective control of maternal seizures with the least risk to the fetus is the goal. Careful planning and management of any pregnancy are essential to increase likelihood of a healthy outcome both for the mother and the baby. Some guidelines for woman with epilepsy will be introduced. The elderly are the most rapidly growing part of our population, and the prevalence of epilepsy is also rapidly increasing in this group. Age-related physiologic changes in hepatic and renal function, volume of distribution, and exaggerated sensitivity to side effects should de considered. The elderly with a systemic disease such as cardiovascular disorder and renal and hepatic failure require a more complex approach. Epilepsy is a common occurrence in individuals with mental retardation. The degree of mental retardation, associated behavioral disorders, and the type of epilepsy or epileptic syndrome can affect the treatment modality and prognosis. The treatments should be tailored to the needs of individual patients. Comprehensive management requires the involvement of an interdisciplinary team to enhance functioning and achieve optimal quality of care.