One of the surprising oversights of existing research on racially/ethnically diverse congregations is the inattention to how racial composition relates to patterns of attendance. Is diversity associated with attendance growth, stability, or decline? A popular assumption from the Church Growth Movement is that cultural homogeneity is a foundation for growth, but recent research challenges this long standing belief. We test these competing views with longitudinal data from over 10,000 congregations in the Evangelical Lutheran Church in America (ELCA). We examine the relationship between changes in racial/ethnic diversity and changes in average weekly attendance over a 19-year time period (1993-2012). In spite of the ELCA's denominational push for racial diversity in its local churches, our analysis finds increasing racial diversity associated with decreasing average attendance, most notably during the 1990s. To conclude, we discuss the implications of our findings for congregations and denominations.