This study was conducted to determine and compare the effectiveness of nature sounds and relaxation exercises for reducing preoperative anxiety. A repeated measures randomized controlled trial design was used. We divided 159 preoperative patients into three groups: nature sounds (n = 53), relaxation exercises (n = 53), and control groups (n = 53). We evaluated anxiety using the visual analog scale and state anxiety inventory scores immediately before, immediately after, and 30 min after interventions in nature sounds and relaxation exercises groups, and silent rest in the control. We found no differences between the measurement values in the intervention groups, but we did observe a difference between the intervention and control groups. The two interventions were similarly effective in reducing preoperative anxiety. These simple and low-cost interventions can be used to reduce preoperative anxiety in surgical clinics.