ABSTRACT Objectives: • To study the utilization patterns of AEDs and to compare these to previously obtained data at SQUH and international studies. To examine the Therapeutic Drug Monitoring (TDM) requests for AEDs and their obtained concentrations/values. Method: Data was collected retrospectively over a 4-year period from January 2006 to December 2009 from the Electronic Patient Records (EPR). The study included adult epileptic patients on AED follow up at Neurology unit, SQUH. All reported TDM requests for serum anticonvulsant concentrations were collected. Data were recorded in a well designed data collection form. Statistical Package for Social Sciences (SPSS-15) and Microsoft Office Excel® software 2007 were used for statistical analysis. Ethical approval was obtained from the ethics research committee of College of Medicine and Health Sciences at Sultan Qaboos University (SQU) before conducting the study. Results: Three hundred and seventy two adult patients (n=372) were included in the study. AED monotherapy accounted for 53.2% of prescriptions, whereas polytherapy with two and three AED combinations accounted for 26.6% and 20.2%, respectively. The most frequently prescribed AED was sodium valproate (27.1%) followed by carbamazepine (23.3%). The commonly prescribed AED combinations were sodium valproate with clonazepam (12.2%) followed by sodium valproate with lamotrigine (11.9%) and phenytoin with levetiracetam (10.1%). Results of 574 TDM requests for three AEDs were analyzed. Of these, 56.9% of carbamazepine, 77.6% of phenytoin and 54.2% of valproic acid requests disclosed serum concentrations above or below the recommended therapeutic range. Conclusion: AED monotherapy is still the most frequently employed therapeutic strategy in adult patients with epilepsy in keeping with the standard therapeutic guidelines. Sodium valproate is commonly used for different types of seizures spectrum of anticonvulsant potential. Newer AEDs such as lamotrigine, levetiracetam and topiramate utilization are becoming increasingly popular in our subjects particularly as add-on with other standard AEDs. The majority of TDM requests for carbamazepine, phenytoin and valproate need to be explored further for deciphering abnormal serum concentrations. Keywords: antiepileptic drugs, carbamazepine, phenytoin, valproate, clonazepam, lamotrigine, levetiracetam, topiramate, utilization patterns, therapeutic drug monitoring, epilepsy.