Ninety-three adult ASA I–III E patients undergoing emergency laparotomies were investigated in this research. Subjects were randomly divided into three groups. Following general anesthesia, bilateral peripheral nerve blocks guided by ultrasound Transversus abdominis plane block (TAPB) or erector spinae plane block (ESPB) were administered. Pain scores at rest and movement, time to first analgesic request, and total fentanyl consumption were recorded postoperatively and compared. Pain scores at rest were significantly reduced in the research groups for 12 and 18 h in TAPB and ESPB, respectively, also there was a significant decrease at 2, 4, 6, and 8 h in the ESPB group compared to the TAPB group. While pain scores at movement were significantly reduced in the ESPB group for the first 8 h than in the TAPB group both study groups demonstrated significantly reduced pain scores than the control group for the first 8 h for the ESPB group and the first 4 h for TAPB group. The time to first analgesic demand was longer in the ESPB group than in the TAPB group and both study groups were longer than the control group. Fentanyl consumed in the ESPB group was reduced than in the TAPB group and both study groups were reduced than the control group in the first 24 h. For patients having emergency laparotomies, bilateral ultrasound-guided ESPB with 40 ml of 0.25% bupivacaine reduces pain scores both at rest and motion, fentanyl use, and extends the duration of analgesia postoperatively compared to bilateral ultrasound-guided TAPB.