Background: Epilepsy is a common chronic neurological disorder affecting around 5million people each year worldwide, it is estimated that nearly 70% of people with epilepsy could live seizure free if properly diagnosed and treated, so early diagnosis and treatment is very helpful. Methods: This cross sectional observational prospective study included 36 epileptic patients underwent long term Electroencephalographic monitoring for at least sixty minutes and epilepsy severity was measured by National Hospital Seizure Severity Scale. Results: 52% of studied patients had late IED beyond 20 minutes of EEG recordings, while 30.1% of our patients had early IED in the first 20 minutes of EEG recording .also Interictal Epileptiform discharge (IED) latency had significantly increased with earlier age of epilepsy onset (22.13 ± 12.8 vs. 42.33 ± 4.2, P= 0.01) and longer duration of epilepsy (13.40 ± 4.6 vs. 8.50 ± 3.9, P= 0.027). Conclusion: Our data concluded that age of onset and duration of epilepsy were significant factors related to the presence of IED, as patients with IED had an earlier onset and longer duration of epilepsy.