Purpose To evaluate the effectiveness of localized sub-Tenon's anesthesia for pain control during 23-gauge vitreoretinal surgery. Methods Eighty patients were randomly divided into two groups as localized sub-Tenon's (group 1,n = 41) and retrobulbar (group 2,n = 39) anesthesia groups. In group 1, a small volume of anesthetic was injected into the sub-Tenon's capsules at the trocar entry sites. The 23-gauge vitreoretinal surgery was performed in all patients. In both groups, the pain levels during the surgical steps were evaluated using the visual analog pain scale. Results Patients in group 1 experienced less pain than group 2 patients did during placement of the trocars and scleral depression (p = 0.041,p = 0.029). Pain during laser photocoagulation was higher in group 1 (p = 0.008). There was no serious complication due to anesthesia or surgery. Conclusion Localized sub-Tenon's anesthesia is as effective as retrobulbar anesthesia in many steps of vitreoretinal surgery for providing pain control. It can be considered an alternative form of local anesthesia.