Background <p>Epilepsy has a significant impact on individuals’ lives, as well as on society and the economy, due to its unpredictable nature and the financial burden it places on those affected. Even though Thai citizens hold health benefits or health insurance, excess costs can occur; thus, this study aimed to describe the direct medical costs among hospitalized patients with epilepsy from both social and patient perspectives. Moreover, the factors associated with costs were investigated.</p> Methods <p>This was a prevalence-based cost-of-illness study using data from the Thailand National Health Security Office database. Patients who were diagnosed with epilepsy (ICD-10 code G40) and admitted to the hospital in the fiscal year 2022 were included. Direct medical costs were reported from societal and patient perspectives. A generalized linear model with gamma distribution and log-link function was employed to investigate the factors influencing these costs.</p> Results <p>Among 31,635 epilepsy visits, the mean direct medical costs from a societal and patient perspective were 1,043.45 PPP-USD and 14.02 PPP-USD per visit, respectively. From a societal perspective, patients who underwent procedures experienced a substantial increase of 120.9% in costs compared to those without procedures, while hospital stays exceeding one week showed a significant 750.1% increase in costs compared to shorter stays. Furthermore, female sex, older age, and the presence of comorbidities or complications significantly increase costs. From the patient’s perspective, those with comorbidities or complications during admission had a 56.0% increase compared to those without such conditions. Moreover, elderly patients, those who underwent procedures, and individuals with extended hospital stays were associated with increased costs.</p> Conclusions <p>Factors influencing costs were hospital stay duration, comorbidities or complications, and types of procedures.</p>