Background: Postoperative shoulder pain is one of the most common complications following laparoscopic surgery. Various interventions have been proposed to control this pain. Objectives: The main objective of this comparative study was to determine the effects of intraperitoneal bupivacaine and normal saline infusion, in combination with lung recruitment maneuver (LRM), on shoulder pain following laparoscopic surgery. Methods: The present randomized controlled trial was conducted on 105 candidates for laparoscopic cholecystectomy referred to Imam Ali Hospital in Bojnurd, Iran, from November 2021 to June 2022. The patients were assigned to three groups using block randomization: BR (receiving 50 cc of 0.25% diluted intraperitoneal bupivacaine + LRM), NR (receiving 50 cc of intraperitoneal normal saline + LRM), and N (receiving 50 cc of intraperitoneal normal saline). Postoperative shoulder pain and surgical incision site pain were assessed using the Visual Analogue Scale (VAS) at recovery intervals of 4, 12, 24, and 48 hours after surgery. Additionally, the prevalence of nausea and vomiting, the first time of need for sedation, and the incidence of sedation overdose in the first 24 hours after surgery were investigated. The data were analyzed using one-way analyzed by one-way analysis of variance (ANOVA) with SPSS software at a significance level of 0.05. Results: The findings showed no significant differences in demographic variables between the three groups. The range and mean score of shoulder pain based on VAS was 0 - 1 (0.3) in the BR group, 0 - 2 (1.4) in the NR group, and 1 - 3 (2.1) in the N group at 4 hours after surgery. The mean score of shoulder pain intensity in the BR group was lower compared to the NR and N groups during recovery time intervals at 4, 12, and 24 hours after surgery. This difference between groups was significant. There was also a statistically significant difference in the mean score of surgical incision site pain intensity and the first time of need for sedation between the three groups. The occurrence of side effects was not significant between the groups. Itching, bradycardia, and hypotension were not observed in any of the groups. Conclusions: The findings of this study showed that bupivacaine, along with LRM, is a safe method effective in relieving postoperative shoulder pain. It prolonged the first time of need for sedation and significantly reduced the incidence of shoulder pain.