Background: Cardiac arrhythmias are not uncommon during and after coronary artery bypass graft cardiac surgeries. Preliminary studies showed the preventive effects of stellate ganglion block upon cardiac arrhythmias; however, this could be the 1 st study focusing upon intraoperative arrhythmias during offpump coronary artery bypass graft surgery as a main goal. Methods: This is a randomized controlled trial. The study involved forty adult patients undergoing elective offpump coronary artery bypass graft surgery. Twenty patients received left SGB with 10 ml of 2% lidocaine before induction of anesthesia (B group), and twenty patients as a control group (A group). Intraoperative and 24-hours postoperative electrocardiogram and hemodynamics were monitored, in addition to the mean postoperative 24-hours inotropic score. Results: There was a significantly higher incidence of intraoperative arrhythmias in the control group in the form of bradyarrhythmia (25%), supraventricular tachycardia (30%), atrial fibrillation (5%), ventricular tachycardia (10%), and ventricular fibrillation (5%) in comparison to the block group where atrial fibrillation occurred only in 4 patients (20%) with the p value of 0.007. Mean arterial blood pressure and heart rate showed significantly lower values in the SGB group intraoperatively. Postoperative mean 24-hour inotropic score and hemodynamics showed insignificant differences. Conclusion: Preoperative left stellate ganglion block can decrease incidence of arrhythmias during offpump coronary artery bypass graft surgeries. The technique showed a safe profile upon hemodynamics during the study period.