Kampala, Uganda - The Anglican Church in Uganda is to boycott the Lambeth Conference, a meeting of the world's Anglican bishops held once every 10 years.
The move is in protest at invitations being sent to bishops who condone active homosexuality.
The extent of the boycott was unclear but a significant number of bishops would be absent, said BBC religious affairs correspondent Robert Pigott.
The gathering in July is convened by the Archbishop of Canterbury.
'Disintegrating communion'
This year is widely considered to be a critical year for the unity of the Anglican Communion.
However, our correspondent said the decision of the Ugandan Church, which has 8 million members, will further undermine the slender chances of holding the disintegrating communion together.
Traditionalist Anglican churches in developing countries have been threatening for some time to turn their backs on Lambeth.
They object to bishops with a liberal approach to homosexuality from the American wing of the communion being invited.
The Ugandan Church cited the American Church's ordination of the openly gay bishop Gene Robinson in 2003 and continued blessing of same-sex relationships as reasons for the boycott.
It said its bishops would attend an alternative conference organised by traditionalists in Jerusalem instead of Lambeth.
Canon Dr Chris Sugden of the Anglican Mainstream, a network of orthodox churches and parishes, said it was no surprise the Ugandan church would not be represented at the Lambeth meeting.
"This is not out of the blue, they have constantly been raising this issue [Gene Robinson] but nothing has been done, so they're not coming."
He said neither Uganda, Nigeria, Kenya nor Rwanda would be represented at the June gathering, covering some 30 million members.
"The Lambeth conference won't be representative of 50% of the Anglican Communion."