Cardiac implantable electronic device (CIED) procedures can cause significant post-operative pain. Opioid use for post-operative pain is associated with risk of persistent use. The benefits of pectoral nerve blocks (PECs) have been established for other chest wall surgeries but adoption in electrophysiology has been limited. To evaluate the efficacy of intraoperative ultrasound guided PECs performed at the time of CIED procedures by the implanting physician from within the device pocket. Patients undergoing a pectoral CIED procedure at 7 centers from 2022-2023 were included. Patients underwent intraoperative PECs and subcutaneous local anesthetic vs subcutaneous local anesthetic only at the discretion of the operator. Patients were prospectively evaluated for post-operative pain. 610 patients (67±15 years old, 63% male) were enrolled and half (n=305) underwent PECs. Patients who underwent PECs were more likely to have a history of chronic pain (32 vs 11%, p<0.001). PECs was associated with lower pain scores in the 4 hours after the procedure (1.5±2.1 vs 4.5±2.5, p<0.001). Pain scores were not different after 24-hours (2.8±1.7 vs 3.1±2.2) and 2-weeks (0.9±1.4 vs 0.9±1.2). PECs patients were less likely to receive inpatient opioids (10 vs 48%, p<0.001) and to be discharged with an opioid prescription (15 vs 59%, p<0.001). In multivariable linear regression, PECs (p<0.001), age (p=0.002) and absence of chronic pain (p=0.009) were associated with lower acute post-operative pain. Intraoperative PECs can reduce post operative pain and opioid use. This procedure can be readily performed by the implanting physician from within the device pocket.