This study examines the effect of relaxation exercises on controlling postoperative pain in patients who have undergone upper abdominal surgery. This is a cross-sectional and crossover study conducted on 60 patients who underwent upper abdominal surgery between October 2006 and June 2007, in the General Surgery Department, Health and Research Practice Center, Trakya University, Edirne, Turkey. We assessed the patients' pain levels before and after the relaxation exercises. Patients' personal information forms were used to collect data, and pain levels were determined using the verbal pain scale. We used the Wilcoxon T test, nonparametric Spearman correlation analysis, and nominal by interval eta analysis to assess the data, percentage, and frequency analyses. Pain levels were found to be reduced after the relaxation exercises compared with the levels before the relaxation exercises (z = −5.497;p< .001). Relaxation exercises, a nonpharmacologic method, are effective in reducing postoperative pain and should therefore be included in a regimen to control postoperative pain in patients who have undergone upper abdominal surgery.