The relevance of family income for religious participation in the United States has been largely ignored in recent decades. Addressing this neglect, we focus our attention primarily upon white Catholics, the poorer of whom we reason have fewer options to participate in the context of an increasingly middle-class Church. Analyzing the 1972-2006 cumulative General Social Survey data, we show that net of all other factors low-income white Catholics attend church less often than other white Catholics, although social integration mechanisms significantly moderate the effects of income. Additional analyses suggest that the effects of income on church attendance are greatest for the younger white Catholic cohort. In contrast, the role of income in Latino Catholics' attendance is relatively weak. In our conclusion, we attempt to integrate our most puzzling finding--having children in the home does not increase the church attendance of low-income white Catholics--with our main theoretical line of argument concerning the central role of social integration in understanding the impact of income on religious participation. (Contains 17 notes, 4 tables, and 5 figures.)