Epidemiological parameters of epilepsy have been estimated in a large number of studies. Reported annual incidence rates for recurrent seizures vary between 30 and 50/100,000, and prevalence rates in most studies between 500 and 1000/100,000. Varying findings are mostly due to different case ascertainment methods and definitions of epilepsy applied in different surveys. These aspects will be discussed in this paper. A special emphasis is laid on differential diagnosis of seizure disorders, and on the prevalence and causes of complex partial epilepsy. This epileptic disorder is one of the most common forms of epilepsy, and also difficult to treat in many cases. Many recent reports show that prognosis of seizures in patients with epilepsy is better than suggested in earlier studies. However, 25-30% of epileptics seem to have frequent (greater than 1/month) seizures. Our own study, in accordance with earlier findings suggests that prevalence of patients with severe complex partial epilepsy is about 80-90/100,000. Available literature provides several predictive factors for the prognosis of seizures and assessment of prognosis is possible quite early after the onset of seizures. Treatment choices for patients with intractable epilepsy will be discussed.