Background: Hemorrhoid is one of the most common surgical diseases occurring in the anorectal region. In this study, we evaluated the effect of ischiorectal fossa block on alleviating post hemorrhoidectomy pain. Methods: In this study, 90 patients suffering from hemorrhoids were evaluated. They were randomly divided into 3 groups. The first group had no block, the second group an ischiorectal block with placebo (normal saline), and the third group a preemptive ischiorectal block with bupivacaine. Postoperative variables such as pain intensity, pethidine consumption, nausea, and vomiting were compared between the groups. Results: The postoperative pain score in group 1 was $8.5{pm}1.3$ and $8.1{pm}0.9$ (P=NS) in group 2. The post operative analgesic demand was $3.1{pm}1.5$ and $3.3{pm}1.8$ hours in groups 1 and 2, respectively (P=NS). The post operative pain score and analgesic demand were $4.2{pm}2.1$ and $9.3{pm}2.7$ hours, respectively, in group 3 (P < 0.0001). Conclusions: Preemptive ischiorectal block reduces the posthemorrhoidectomy pain and opioid demand.