Background: The number of cardiac arrest patients who are resuscitated has increased with the development of emergency medical services. Brain swelling is often found in these patients, following return of spontaneous circulation. This study identifies risk factors for brain swelling, describes it`s frequency, analyzes the effect of brain swelling on neurological outcome, and compares the results with other studies. Methods: A retrospective analysis had been conducted on cardiac arrest patients who visited the emergency room at a university hospital during a 24 month period since 2007. Thirty-seven successfully resuscitated patients were divided into 2 groups based on computed tomography findings; these groups consisted of 14 patients with brain swelling and 23 patients without brain swelling. Comparative studies were conducted on post-lab findings and several additional factors. Results: The 14 patients with brain swelling were significantly younger and showed a higher clinical performance category score than patients without brain swelling. Initial serum lactic acid levels showed good correlation with brain swelling. Conclusions: An urgent CT should be conducted and aggressive treatment pursued when brain swelling is suspected, after consideration of various prognostic factors.