In recent decades researchers have investigated the effectiveness of prayer by designing clinical trials using distant intercessory prayer as a treatment method for a variety of health conditions. Some studies claim to demonstrate a statistically significant result while others show no effect. This article surveys the most significant of these studies to determine if they demonstrate what their authors claim. The paper argues that clinical trials using prayer as a treatment option are not an appropriate subject for scientific investigation. In addition, it raises several theological objections to the assumptions underlying these studies.