This study was conducted to determine the effects of Reiki on pain and vital signs when applied for 15 minutes to the incision area of the body after cesarean section surgery. The study was single-blinded, randomized, and double-controlled (Reiki, sham Reiki, and control groups). Forty-five patients, equalized by age and number of births, were randomly assigned to the Reiki, sham Reiki, and control groups. The treatment, which was applied to the patients in these 3 groups, was applied for 15 minutes to the incision area of body in the first 24 and 48 hours after the operation within 4 to 8 hours of the application of standard analgesics. The study data were collected using a patient follow-up form and a visual analog scale. Mean visual analog scale measurement values were significantly different from each other according to groups and times (P<.05). A reduction in pain of 76.06% was determined in the Reiki group patients between day 1 pre-tx and after application on the second day (day 2 post-tx) measurements. Mean breathing rate and systolic blood pressure measurement values were significantly different from each other according to groups (P<.05). The Reiki group was observed to use fewer analgesics throughout the study and to need them after a longer time than the sham Reiki and control groups (P<.05). It was concluded that Reiki applied for 15 minutes to the incision area after a cesarean operation had the expected effects on pain and the need for the use of analgesics, but it had no effect on vital signs.