Dexmedetomidine is a selective α-2 adrenoceptor agonist with anxiolytic, sedative, and analgesic properties that prolongs analgesia and decreases opioid-related side effects when used in neuraxial and perineural areas as a local anesthetics adjuvant. The current study was designed to evaluate the effects of a single perineural administration of dexmedetomidine without local anesthetics on narcotic consumption and pain intensity in patients with femoral shaft fractures undergoing surgery. This prospective randomized single-blind clinical trial was conducted in patients undergoing femoral fracture shaft surgery. Based on block permuted randomization, the patients were randomly divided into intervention and control groups. The intervention group received 100µg dexmedetomidine, for a femoral nerve block without any local anesthetics. Total intraoperative opioid consumption, postoperative opioid consumption, visual analogue score (VAS) for pain, and hemodynamic parameters were recorded and compared. Finally the data from 60 patients with a mean age of 30.4±12.3 were analyzed (90% male). There were no significant differences between the baseline characteristics of the two groups (p>0.05). The mean total consumption of narcotics was reduced during induction and maintenance of anesthesia in the intervention group (p<0.05). The amount of postoperative narcotics required showed a significant difference in the intervention group compared with the control group (p<0.05). It is likely that perineural administration of dexmedetomidine significantly not only reduced intra and postoperative narcotic requirement but also decreased postoperative pain intensity in patients undergoing femoral shaft surgery. Femoral blockade by dexmedetomidine can provide excellent analgesia while minimizing the side-effects of opioids.