There was no immediate reaction from the military to the Tiger losses.
The military has admitted losing over 15,000 security personnel in the conflict.
The Liberation Tigers of Tamil Eelam (LTTE) announced their losses since the first guerrilla fatality at the hands of government forces nearly 25 years ago as they marked their "Heroes' Week."
The commemoration ends Tuesday with an annual policy statement by Tiger chief Velupillai Prabhakaran.
The rebels usually hold Hindu religious observances to honour their dead, who joined the fight for independence for the Tamil minority in the majority Sinhalese nation.
Documents released by the LTTE showed that 19,887 of their members have been killed since November 1982, when the first Tiger loss was recorded though the organisation was formed 10 years earlier.
Among the dead were 343 suicide bombers, including 93 women, who staged devastating attacks, mainly against security forces.
The LTTE said 950 of their cadres have been killed