Febrile seizures are the most common type of convulsion in children. Frequent studies have been conducted on the relation between febrile seizures and micronutrient deficiency. Recent studies have shown that selenium deficiency plays a major role in catching epilepsy. The current study was conducted to determine the relationship between serum selenium level and simple febrile seizure. In this cross-sectional descriptive study, children aged 9 months to 5 years suffering from febrile seizure entered the study, who had been hospitalized in Shahid Madani Hospital of Khorramabad in the first half of 2014. Sampling technique was accessible method based on children's inclusion criteria. Among children aged between 9 months and 5 years, 38 subjects diagnosed with simple febrile seizures, 38 children with fever and no seizures, and 38 children aged between 9 month to 5 years, without febrile seizures were selected through accessible sampling method. They were similar to children with febrile seizure in terms of age and gender. Serum selenium level was measured using atomic absorption spectrophotometer. Data related to anthropometric indices, age, gender and location of children were collected using three questionnaires. To compare serum selenium level among these three groups, one-way analysis of variance (ANOVA) or its non-parametric alternative (Kruskal-Wallis test) was used. To measure the relation between demographic variables and serum selenium level, chi-square tests were employed (by converting serum selenium level to dual-mode quality variable). Average selenium level was 76.41±22.31, 78.85±19.2 and 87.28±16.3 in children with febrile seizures, fever with no seizure group and no febrile seizure group, respectively and it showed a significant difference according to ANOVA (pv=0.048). In post hoc analysis, the difference was observed between children with febrile seizures and no febrile seizures' group along with children with fever and no seizures and no febrile seizures' group. In post hoc analysis, the difference between serum selenium levels was not statistically significant between two groups of children with febrile seizures and those with fever and no seizure. In the present study, a decrease of serum selenium level was observed in children with febrile seizures along with children with fever. However, more future studies are recommended.