In laparoscopic surgery (LS) for colorectal cancer (CRC), the relationship between intraoperative end-tidal carbon dioxide concentration (EtCOIn total, 909 patients who underwent LS for CRC were enrolled. Hypocapnia and hypercapnia were defined as EtCOThe median (range) durations of hypocapnia and hypercapnia were 2.0 (0-8.3) h and 0.3 (0-5.8) h, respectively. Complications were observed in 208 cases (23.0%), which included 37 (4.1%) instances of anastomotic leakage and 86 (9.5%) of superficial surgical site infection (SSI). While the hypercapnia duration was not associated with the short-term outcomes, prolonged hypocapnia was significantly correlated with complications (p = 0.02), specifically superficial SSI (p = 0.005). Multivariate analyses adjusted for confounding factors confirmed that hypocapnia prolongation was an independent risk factor for postoperative superficial SSI [OR 1.19; 95% confidence interval (Cl) 1.03-1.36, p = 0.01].Intraoperative hypocapnia may be a risk factor for postoperative complications, in particular superficial SSI, in LS for CRC.