The United States (black) is the home of the Church of the Brethren. Several churches are also present in Puerto Rico (black).

Missions have been open in Haiti since 2003.

Missions began in Brazil in the 1950s.

Puerto Rico first sent missionaries to the Dominican Republic in 1979.

Several Protestant churches began work in Ecuador through the United Andean Indian Mission in 1946. The Church of the Brethren arrived in 1963 and these bodies merged into the United Evangelical Church of Ecuador in 1965 (renamed the Evangelical Methodist Church of Ecuador in 1999.)

Missions work in Argentina was mostly concentrated in the Córdoba Province for a few years in the middle of the 20th century.

Work in Niger was initiated by Nigerian Brethren after a 1972–73 drought.

Missions in Nigeria began in 1923 and membership exploded after the Second World War. Today, Nigeria has slightly more Brethren than the United States, concentrated in the eastern states of Borno and Gongrola (as well as Oku, Cameroon.)

Brethren have been working with refugees in Southern Sudan since the 1980s.

Missions begun by the Danish-American preacher Christian Hope had modest success in northern Denmark and southern Sweden starting in the late 1870s and lasting through World War II.

Dutchman G. J. Fercken had small missions in France and Switzerland in the first two decades of the 20th century.

Brethren assisted in China (magenta) during a 1918 plague and a famine from the early 1920s. After the invasion of China by the Japanese in 1937, Brethren attempted to establish a lasting presence, but their effectiveness vacillated with government interference and social stability. Chinese Brethren got absorbed into the house church and mainstream Protestant movements in the 1970s and 1980s.

Brethren first established themselves in the Indian state of Gujarat in 1894 and eventually merged with several other Protestant groups in 1970 to form the Church of North India. A single Brethren church refused membership and maintains ties to the United States Church of the Brethren as of 2010.

After hearing about the Armenian/Assyrian Genocide in 1917, Brethren set up a small mission in İstanbul which lasted until 1921.

Brethren briefly had missions in the eastern archipelagos of Ambon and Sulawesi in the mid-20th century.

Spain received recognition from the denominational board in 2013