The 11th victim of the disease was a 72-year-old woman who reportedly contracted the virus at a hospital that was at the center of the outbreak.
A total of 126 people are estimated to be infected so far.
The number of people quarantined in South Korea amid the outbreak exceeds 3,400 people. More than 2,000 educational facilities have been closed to prevent the spread of the virus.
The South Korean government has acknowledged that the outbreak has been fueled by insufficient safety measures when the first MERS patients were hospitalized.
The Middle East Respiratory Syndrome is a viral respiratory disease caused by the MERS-coronavirus. First reported in 2012 in Saudi Arabia, it has since spread to other countries.
Fever, coughing and a shortness of breath are among the typical symptoms of MERS.