Background <p>Conventional abdominal wall blocks primarily target somatic afferent nerves and may therefore provide limited relief for the peritoneal component of postoperative pain. This study aimed to investigate whether a laparoscopic-guided deep rectus sheath (preperitoneal) block (RSB) could reduce postoperative opioid consumption and improve postoperative pain in patients undergoing laparoscopic cholecystectomy.</p> Methods <p>Patients were randomly assigned to either the control group or the deep RSB group. In the deep RSB group, the block was performed intraoperatively under direct laparoscopic visualization. No block was performed in the control group. In the deep RSB group, postoperative ultrasound assessment was used to verify bilateral local anesthetic localization. Postoperatively, all patients were connected to an intravenous patient-controlled analgesia device containing morphine. The primary outcome was cumulative morphine consumption within the first 24 postoperative hours.</p> Results <p>Cumulative 24-h morphine consumption was significantly lower in the deep RSB group, with a median difference of − 9&#xa0;mg (95% CI − 11 to − 6; <i>p</i> = 0.0001). Pain scores at rest and during movement were significantly lower in the deep RSB group at 2, 6, and 12&#xa0;h postoperatively, with no significant difference observed at 24&#xa0;h. Rescue analgesia requirement and incidence of postoperative nausea and vomiting were similar between groups. Quality-of-recovery scores at 24&#xa0;h were significantly higher in the deep RSB group.</p> Conclusions <p>Laparoscopic-guided deep RSB significantly reduced postoperative opioid consumption and improved early postoperative pain control after laparoscopic cholecystectomy. Targeting the preperitoneal plane under direct laparoscopic visualization may enhance early multimodal analgesia in these patients.</p> Trial registry <p>ClinicalTrials.gov identifier: NCT06976320.</p>