"He was declared dead at 1:43 pm (local time)," a spokesman for Seoul's Severance Hospital said.
"His heart began failing at 1:35 pm and stopped minutes later despite our efforts to revive it."
Kim who was president from 1998-2003 was admitted to hospital on July 13 with pneumonia and other symptoms.
He held South Korea's first-ever summit with North Korean leader Kim Jong-Il in 2000 and was awarded the Nobel prize later that year for his efforts.
(Published 18 August 2009, 05:44 IST)