BACKGROUND: Since May 2009, a pandemic influenza A (H1N1) virus has emerged and spread nationwide. We describe the epidemiological characteristics of the confirmed deaths related with the 2009 H1N1 influenza pandemic in Korea from May 2009 to mid December 2009. METHODS: This study was based on an analysis of the reports from the deaths of confirmed cases pandemic H1N1 virus until 7 December 2009 in Korea. These reports were compiled by the epidemic intelligence team at the Korea Centers for Disease Control & Prevention (KCDC) or at the provinces. The epidemic intelligence team used an identical, well-defined investigate form for reviewing the medical records and for interviewing the physicians in charge of the cases. RESULTS: The first confirmed death occurred on August 15, 2009. Until December 7, 2009, 139 deaths had been reported. Eighty cases (57.6%) were individuals more than 60 years old. Sixty two cases (47.0%) were dead within 7 days from the onset of symptoms. One hundred three cases (74%) had underlying diseases, and cancer was the most common underlying disease. The proportion of patients using antivial medications before confirmation among the patients with underlying diseases was greater than the proportion of patients using antivial medications among the patients with no underlying diseases. CONCLUSIONS: During the evaluation period, serious underlying diseases were present in nearly three quarters of the cases of confirmed death. We suggest that health providers consider using antiviral drugs before confirmation of pandemic H1N1 in hospitalized patients, and especially in those with underlying diseases.