DESCRIPTION When compared to developed countries, studies of seizures and epilepsy in Latin American report higher prevalence and incidence. Whether these differences are due to methodological issues or to factors related to the health system structure in developing countries, such as poor perinatal care, malnutrition, head injury and infectious and parasitic diseases remains unanswered. The current proposal is an hypothesis testing and generating case-control study. Cases (individuals with newly identified single or recurrent unprovoked seizures) will be selected from all patients attending a major general hospital in Quito, Guayaquil or Cuenca, the largest cities of Ecuador, South America. For each case, two controls matched by age and gender will be selected randomly from among the population seeking medical care at the same hospital and who have conditions unrelated to any neurological disorder. The log odds ratios for putative risk factors for epilepsy in cases and controls as well as the 95% confidence limits will be calculated. Summary odds ratios will be calculated by means of the Mantel-Haenszel method. Additionally, logistic regression analysis will estimate odds ratios adjusted for confounding variables and systematically appraise effect modification. This study can provide further understanding of the mechanisms associated with known risk factors for epilepsy, and evaluation of potential risk factors related to deprived health care systems such as perinatal trauma, malnutrition, and infectious and parasitic diseases (i.e. cysticercosis). This study can provide data leading to specific interventions which will allow a reduction in the frequency of epilepsy.