"All possibilities to reschedule this show are being explored," said a spokesperson for the former Beatle.
The cancelation comes shortly after the 71-year-old called off two shows in neighboring Japan due to illness.
"After coming down with a virus in Japan, doctors have ordered Paul complete rest. Paul is still not feeling better and this cancelation is unavoidable," said the spokesperson.
The singer expressed his regrets, saying: "I was really looking forward to visiting and playing in South Korea for the first time and I’m sorry to be letting fans down. I'm very disappointed by this and hope to be able to visit soon."