A two-group pretest and posttest quasi-experimental design was used to determine the effectiveness of a slow, deep-breathing relaxation technique in relieving postoperative pain after coronary artery bypass graft surgery. A convenience sample of 29 subjects was divided into an experimental group (n = 15), who received relaxation training on the evening before surgery and performed the technique after surgery, and a control group (n = 14), who did not receive relaxation training. Analysis of variance was used to analyze the data. Significant decreases were demonstrated as a result of relaxation, in blood pressure, heart rate, respiratory rate, and report of pain on the visual descriptor scale. No significant differences were seen in analgesic use or visual analogue scale scores. Eleven subjects (73.3%) said the technique was helpful in their pain management. All experimental subjects stated that the relaxation technique was simple to perform, and they would recommend it to others who have postoperative pain.