This paper describes how marriages between Catholics and Protestants, especially Lutherans, Sevenths Day Adventists, and Anglicans happen in Tanzania and identifies lessons for ecumenism from such marriages. Based on tentative findings drawn from field research, I argue that although marriages between Catholics and protestants are not free from doctrinal and practical challenges, they nevertheless epitomize the anatomy and grammar of ecumenism at grass-root level, from which the official church can borrow a leaf or two so as to overcome the shame of Christian disunity that has been going on for more than five hundred years now. I maintain that in order to overcome the current crisis and impasse looming on the ecumenical movement, there must be real dialogue between the approach of the official church and ordinary Christians involving genuine willingness from both sides to give and take as evidenced in mixed marriages.