Febrile seizures (FS) are one of the most common neurological problem amongst children from ages 6 months to 5 years. Any illness that affects the brain or metabolic imbalance should not be involved by definition and they are mostly considered benign. Yet the patients often visit the emergency room or are admitted due to its unanticipated character. We aim to explore the risk factors of febrile seizures in children, especially on the account of its clinical and laboratory manifestation presented at admission. We have collected 310 febrile seizure patients who visited Kangdong Sacred Hospital’s pediatric outpatient clinic or emergency room from year 2012 to 2015 and retrospective review of the medical charts was done. Clinical factors such as onset of seizure from fever development, seizure type, duration of seizure, degree of body temperature, and basic laboratory findings such as white blood cell count, hemoglobin, and c-reactive protein were analyzed. Average age of the patients were 2.16 years old, 8.1% (n = 25) below 1-year old. Amongst the patients that were recorded, 51.3% of them (n = 122) developed febrile seizures on the first of day fever but no significant difference was found in laboratory results when compared to those who had their seizures after more than 1 day of fever. Their fever was recorded at mean body temperature of 38.9 ± 0.80 ℃, and 22.3 % of the recorded patients were checked with high fever of above 39.4 ℃. Family history of febrile seizures were noted in 63 children out of 281. When previous febrile seizures were taken into account, first febrile seizure patients (62.6%, n = 195) tended to have lower hemoglobin and hematocrit levels ( p = 0.034 & p = 0.043 ) but those with recurrent seizures had lower calcium levels ( p = 0.027 ). In contrary to our hypothesis that there may be a prognostic factor for those who develop seizures at early stage of febrile illness, no meaningful finding was found, but patients with low hemoglobin and hematocrit levels may be more susceptible to first onset of febrile seizures.