World Communion Sunday is a celebration observed by several Christian denomination

Christian denomination

A Christian denomination is an identifiable religious body under a common name, structure, and doctrine within Christianity. In the Orthodox tradition, Churches are divided often along ethnic and linguistic lines, into separate churches and traditions. Technically, divisions between one group and...

s, taking place on the first Sunday

Sunday

Sunday is the day of the week between Saturday and Monday. For most Christians, Sunday is observed as a day for worship of God and rest, due to the belief that it is Lord's Day, the day of Christ's resurrection....

 of every October

October

October is the tenth month of the year in the Julian and Gregorian Calendars and one of seven months with a length of 31 days. The eighth month in the old Roman calendar, October retained its name after January and February were inserted into the calendar that had originally been created by the...

, that promotes Christian unity and ecumenical cooperation. The tradition originated in the Shadyside Presbyterian Church

Shadyside Presbyterian Church

Shadyside Presbyterian Church is a large congregation of the Presbyterian Church in an historic part of Pittsburgh, Pennsylvania, United States...

 in 1933, was adopted throughout the US Presbyterian Church

Presbyterian Church (U.S.A.)

The Presbyterian Church , or PC, is a mainline Protestant Christian denomination in the United States. Part of the Reformed tradition, it is the largest Presbyterian denomination in the U.S...

 in 1936, and subsequently spread to other denominations. In 1940, the Federal Council of Churches (now the National Council of Churches

National Council of Churches

The National Council of the Churches of Christ in the USA is an ecumenical partnership of 37 Christian faith groups in the United States. Its member denominations, churches, conventions, and archdioceses include Mainline Protestant, Orthodox, African American, Evangelical, and historic peace...

), led by Jesse Moren Bader

Jesse Moren Bader

Jesse Moren Bader was a 20th century evangelist, ecumenist and global leader. He was a significant and visionary leader during the twentieth century, not only within his own communion, helping establish the World Convention of Churches of Christ but also within the wider church...

, endorsed World Communion Sunday and began to promote it to Christian churches worldwide.