Background and Objective: Post operative pain is one of the important factors affecting recovery from surgery and anesthesia. Gabapentin is used as an anticonvulsant drug that acts through voltage-dependent calcium channels. In some recent studies, oral gabapentin has been reported to reduce post operative pain and morphin consumption following mastectomy and hysterectomy. The aim of the present study was to determine the effect of gabapentin on postoperative pain after abdominal hysterectomy. Material and Methods: In a double-blinded clinical trial design, 50 women aged 35- 50 years old, whom were candidate for hysterectomy referred to Shabih Khani Hospital in 1389, were signed up for the study. Patients received randomly either oral gabapentin 1200 or placebo 1 hr prior to the surgery. Pain was assessed on a visual analogue scale (VAS) at 2, 6, 12, and 24 hr intervals after the operation. Morphine consumption and drug-induced complications such as nausea and vomiting were recorded and compared between the two groups. Results: Factors including age, mean operative time, mean anesthesia time, and BMI were not significantly different between the test and control groups. However, the mean pain scores at 2, 6, 12, and 24 hr after operation were significantly lower in the gabapentin group in comparison to the controls (P<0.0001). The morphin consumption was also significantly lower in the gabapentin group (P<0.0001). Furthermore, the average time before the first to walk following the operation was significantly shorter in the gabapentin group (P=0.002). Conclusion: Preoperative oral gabapentin decreases the pain scores in the postoperative period and lowers the morphine consumption in patients following abdominal hysterectomy.