Sixty patients with unilateral mandibular fractures scheduled for surgery under general anesthesia were randomized to receive an ultrasound-guided mandibular nerve blockade with ropivacaine administered pre-emptively prior to surgical incision (n=30) or post-operation (n=30). The outcomes of interest included morphine consumption, incidence of additional fentanyl consumption, duration of post-operative analgesia, post-operative heart rate and arterial blood pressure, and post-operative pain scores on a Visual Analogue Scale (VAS). Outcomes were assessed up to 24 hours post-operation. Results revealed statistically significantly lower morphine consumption (p<0.0001) and additional fentanyl use (p=0.037) in the pre-emptive group compared to the post-operative group. Moreover, the duration of post-operative analgesia was statistically significantly longer in the pre-emptive group compared to the post-operative group (p<0.0001). In addition, post-operative heart rate was statistically significantly lower in the pre-emptive group between 45 and 120 minutes post-operation (p<0.05 for all); however, no statistical significant differences in post-operative mean arterial pressure were observed between the two groups at any time point (p>0.05 for all). Lastly, VAS pain scores were statistically significantly lower in the pre-emptive group compared to the post-operative group between 8 and 20 hours post-operation (p<0.05 for all).