Purpose: Drowning is a common preventable cause of accidental death. Although many studies about drowning injuries have been conducted, most are related to freshwater drowning. The aim of this study was to analyze the clinical features and prognostic factors in seawater drowning patients. Methods: This study was performed retrospectively with sea water drowning patients who visited the emergency department at Pusan National University Hospital between January 2005 and December 2009. Results: In total, 51 sea water drowning patients presented at the emergency department with a mean age of 48.65±15.40 years. The survival group included 42(82.4%) patients, and the death group was comprised of nine patients(17.6%). Fifteen patients arrested in the field, and cardiopulmonary resuscitation (CPR) was performed. Median immersion time in the death group was 15.0 minutes (range, 9.5~22.5 minutes). Among the death group, five patients had respiratory acidosis and nine showed pulmonary edema on a chest X-ray. Initial sodium level in the survival group was 146.30 mEq/L (range, 142.38~152.60 mEq/L), but the level was normalized with isotonic saline. Conclusion: Most drowning injuries occurred at night and in relatively young aged patients. CPR in the field did not result in good outcomes because of the longer immersion time. The death group had respiratory acidosis. Because the survival group did not show significant hypernatremia, isotonic saline as an initial fluid was thought to be appropriate. Drowning injuries occur differently based on geographic and social characteristics; therefore, local characteristics should be considered to establish preventive measures.