Maintaining deep neuromuscular block during surgery improves surgical space conditions. However, its effects on patient outcomes have not been well documented. We examined whether maintaining deep neuromuscular blockade during surgery could decrease the stress response compared to moderate neuromuscular blockade. Patients undergoing laparoscopic gastrectomy were randomly allocated to either the moderate (train-of-four counts of 1-2) or deep (post-tetanic counts of 1-2) neuromuscular blockade group. The primary outcome variable was the postoperative blood level of interleukin-6, and the secondary outcome variables were intraoperative or postoperative blood levels of tumor necrosis factor-α, interleukin-1β, interleukin-8, and C-reactive protein. A total of 96 patients were recruited and 88 (44 in each group) were included in the analyses. The levels of tumor necrosis factor-α and interleukin-1β measured at the end of surgery, interleukin-6 and interleukin-8 measured at 2 h postoperatively, and C-reactive protein measured at 48 h postoperatively were all significantly increased compared to the preoperative values, but there were no differences between the moderate and deep neuromuscular block groups. We found no differences in surgical stress response measured using determining levels of interleukin-6 and other mediators released between the moderate and deep neuromuscular blockade groups in patients undergoing laparoscopic gastrectomy.