PURPOSE: The purpose of this study was to determine whether the use of a slow deep-breathing relaxation exercise, when used as an adjunct to opioid analgesia, decreases pain during chest tube removal (CTR) after coronary bypass surgery. DESIGN: A two-group quasi-experimental pretest/posttest design was used. SAMPLE: A convenience sample of 40 adults who had undergone coronary artery bypass graft surgery and met all inclusion criteria were recruited before CTR. SETTING: Data were collected in the Cardiothoracic Surgical Intensive Care Units of three acute care facilities in the Midwestern United States.METHOD: A 10-cm vertical Visual Analog Scale was used to measure pain at three points: before CTR, immediately after CTR, and 15 minutes after CTR. The experimental group received slow breathing relaxation exercises in addition to the usual opioid doses administered. FINDINGS: Data were analyzed using analysis of variance, and multivariate analysis of covariance yielded a significant difference in pain ratings immediately after CTR and 15 minutes after CTR for the group receiving relaxation exercise as an adjunct to opioid analgesic. CONCLUSIONS: This study supports the use of a slow deep-breathing relaxation exercise as an adjunct to the use of opioids for pain management during CTR among patients who have undergone coronary bypass surgery. (Heart Lung® 2006;35:269 –276.)