Amish Mennonites came into existence through reform movements among North-American Amish mainly between 1862 and 1878. These Amish moved away from the old Amish traditions and drew near to the Mennonites to become Mennonites of Amish origin. Over the decades most Amish Mennonites groups removed the word "Amish" from the name of their congregations or merged with Mennonite groups.
In the last decades the term "Amish Mennonite" is sometimes erroneously used to designate horse and buggy Old Order Mennonites, whose lifestyle is more or less similar to the Old Order Amish. Sometimes the term "Amish Mennonite" is used to designate all groups of Amish, both the Old Order Amish and the Amish Mennonites and also the Amish before this split in the late 19th century. The Global Anabaptist Mennonite Encyclopedia Online uses the term "Amish Mennonite" in this sense.
From 1862 to 1878, annual conferences were held among the Amish. The conferences produced a number of polarized groups, with two primary divisions: the Old Order Amish and the Amish Mennonites. The Amish Mennonites formed regional conferences in the late 1880s after the division. During the early 20th century, most of these original Amish Mennonite groups merged with regional Mennonite conferences and lost their Amish identity.
The "Conservative Amish Mennonite Conference" was born several decades after the original Amish Mennonite movement. In 1910, leaders from three unaffiliated Amish Mennonite congregations met in Michigan to discuss the formation of a conference that allowed for congregational autonomy yet would be able to assist individual churches with problems. This conference was to be more conservative than the aforementioned Amish Mennonite conferences. Nonetheless it moved closer to mainstream Mennonite groups, eventually losing its Amish identity. In 1954, a majority vote called for the removal of the "Amish" part of the Conservative Amish Mennonite Conference (CMC) name, which was implemented in the 1957 constitution revision. Proponents suggested that "Amish Mennonite" conferences were obsolete.
Leading the process of assimilation further the "Ohio Mennonite and Eastern Amish Mennonite Joint Conference" became the "Ohio and Eastern Mennonite Conference" in 1955 and the "Ontario Amish Mennonite Conference" became the "Western Ontario Mennonite Conference" in 1963.
A number of other Amish Mennonite congregations exist in an independent, unaffiliated setting. Most identify themselves in name as Conservative Mennonites or conservative Amish Mennonite and may hold fellowship with various Beachy or conservative Mennonite congregations.