Roger and Dianne have been missionaries for over thirty years in Europe and Latin America. They met in Europe in 1971, when Roger was a missionary in France and Dianne was a Bible courier behind the Iron Curtain. The Smallings have been involved with church-planting ministries in Guatemala, Mexico, and Ecuador. They joined MTW in 1991. As part of the MTW team in Ecuador, they helped establish the national presbytery there.

The Smallings currently minister throughout Latin America. Their focus is to prepare nationals for Reformed Christian leadership. Roger is director of Visión R.E.A.L (Reformación En América Latina) , the Hispanic branch of Ministries In Action . Visión R.E.A.L is dedicated to bringing the Reformation to Latin America by establishing leadership training centers throughout the region. Dianne ministers to the wives of leaders to encourage their unique gifts in light of their husband's call.