Joint Worship is perhaps the most powerful of all means of inter-religious exchange. Praying together in a shared sacred space brings home to all participants that the God they pray to is the same and that "All Religions Spring From the Same Root".

Oomoto has performed joint worship services with Episcopal and Catholic believers, other Shinto sects, Buddhists, Hinduists, Muslims, representatives of indigenous religions such as American Indians, and many others. Sometimes the worship takes the form of Oomoto ritual; other times it may be a Christian ceremony such as the Kiss of Peace in Ayabe in 1977, or the rites of another religion.

Utamatsuri
The Poem Festival

One of the most striking forms of joint worship at Oomoto is the old tradition of the Utamatsuri, or Poem Festival. Poems written on shikishi (square plaques) are placed on a square altar. topped by an ancient poem calling for the removal of all barriers between peoples. Representatives of different religions place poems or prayers for peace on the altar and pray from the four directions.