The aim of our study was to compare bilateral erector spinae plane block (ESPB) efficacy on pain management with patient controlled analgesia (PCA) during the perioperative period in patients scheduled for coronary artery bypass grafting (CABG). After ethics committee approval (2019-7/31 dated 09.04.2019) from the Bursa Uludağ University Medical Trials Ethics Committee, (https://uludag.edu.tr/buuetikkurulu) ASA II-III, 50 patients aged between 18-80 years were included. They were randomly divided into two groups, ESPB (n=25) and control (n=25). In the preoperative period, bilateral ESPB with ultrasonography was applied to both groups with 0.25% bupivacaine (0.5 ml/kg) + dexamethasone (8 mg) or saline, respectively. PCA prepared with morphine was given to all patients postoperatively. Perioperative opioid use, extubation times, coughing/resting Visual Analog Scale (VAS) scores, duration for first PCA bolus dose requirement, rescue analgesia needs, mobilization times, and opioid side effects were evaluated. In the ESPB group, compared to the control group, intraoperative fentanyl consumption was lower (P=0.001). During the postoperative period; extubation time was shorter, the need for initial PCA was much later, morphine consumption and need for rescue analgesia was less (P=0.001; P<0.001; P<0.001; P=0.009, respectively). The postoperative VAS scores were lower for each measurement period (P<0.05). Opioid-related side effects were more common in the control group (P=0.040). First mobilization time in ESPB group was earlier (P<0.001). As a result, ESPB has a significant analgesic effect in CABG patients. It was concluded that bilateral ESPB reduces opioid requirement compared to intravenous morphine PCA alone and provides better pain management and more comfortable recovery.