After nearly three years of processing throughout the denomination, delegates gathered in San Jose in 2007 strongly voted in favor of Mennonite Church USA joining Christian Churches Together as a full participant. CCT brings together leaders from the various streams of the Christian church: Evangelical, historic Protestant, Pentecostal, Orthodox, Historic Black churches and the Roman Catholic Church. Two or three Mennonite Church USA leaders attend the annual CCT meetings.
For more than twenty years, Mennonites have participated in theological conversations convened by the Faith and Order Commission of the National Council of Churches. Gayle Gerber Koontz, Professor of Theology and Ethics at Associated Mennonite Biblical Seminaries, currently participates in these conversations on behalf of Mennonite Church USA.
In various settings, Mennonites are in conversation and partnership with evangelical leaders and organizations. As is possible, Mennonite Church USA sends representatives to the NAE meetings which are open to non-member churches.