In this article, prayer is represented not as a single or individual action, but as an entirely integrated part of nursing work. Case examples from American, Irish, and Australian Catholic women's religious congregations who nursed in hospitals in the 19th century are used to analyze the significance of prayer to Catholic sisters' nursing. The issue highlighted in this historical examination of prayer is the power of the sickroom (particularly the deathbed scene) in the battle for souls. Sisters' prayers functioned as invitations to religious experiences and means for patients to meet God. Although based on an ancient religion that embraced medieval notions of penance and Counter-Reformation evangelism through good works, sisters' practices, in the turmoil of 19th-century immigration and social upheaval, contributed greatly to the production of the modern hospital and the modern nurse.