Studies have shown that attitudes toward abortion are polarizing. Yet, these studies have not focused upon what is often assumed to be the cause of polarization—religion. In this paper I find that polarization has increased between mainline and evangelical Protestants, as well as between black Protestants and both Catholics and white evangelicals. Moreover, I find that mainline Protestants and Catholics are internally polarizing. Finally, while I cannot determine the cause of the internal polarization of Catholics, the polarization within mainline Protestantism is caused by demographic changes. For white evangelicals, demographic changes have restrained polarization that would otherwise have occurred.