Introduction: Epilepsy is one of the most common disorders of the brain. One of every ten people will have at least one epileptic seizure during a normal lifespan, and a third of these will develop epilepsy. In children the most common forms of convulsion are febrile seizures. Water electrolyte imbalance occurs during acute febrile illness and hypocalcaemia is one of them. Hypocalcaemia is also present in cases of seizures. To find out significance of calcium levels in cases of seizures this study was conducted. Aims: To assess the level of ionized calcium in cases of febrile seizure. Methods: This Case -Control study was conducted on fifty cases of febrile seizures and fifty age, weight matched controls and calcium deficiency determined in both groups. The serum ionized calcium levels were estimated by ion selective electrode method using Na, K, Ca analyzer. Results: Mean ionized calcium level was 4.62±0.26mg/ dl and 4.88±0.27 mg/dl in study and control groups respectively and this difference was found statistically extremely significant (p<0.001). Conclusion: The findings suggest that a considerable percentage of children having febrile seizures are suffering from low level of calcium.