The purpose of this study was to investigate the incidence and risk factors of lower extremity pain and/or numbness after laparoscopic colorectal surgery and robot-assisted laparoscopic radical prostatectomy in the lithotomy position combined with the Trendelenburg position. The relationship between creatine kinase (CK) levels and lower extremity pain and/or numbness was also investigated. We retrospectively reviewed adult patients who underwent laparoscopic colorectal surgery and robot-assisted laparoscopic radical prostatectomy in the lithotomy position combined with the Trendelenburg position between May 2015 and April 2020. Logistic regression analysis was used to identify risk factors of lower extremity pain and/or numbness. Preoperative and postoperative CK levels were compared in patients with and those without lower extremity pain and/or numbness. Among 940 patients, 1.9% experienced lower extremity pain and/or numbness postoperatively. The incidences of lower extremity pain and/or numbness after laparoscopic colorectal surgery and after robot-assisted laparoscopic radical prostatectomy were 1.7% and 2.1%, respectively. Multivariate logistic regression analysis revealed that only duration of surgery > 4h (odds ratio = 3.144, 95% CI: 1.102-8.969, p = 0.032) was a significant predictor of lower extremity pain and/or numbness. Postoperative median CK level in patients with lower extremity pain and/or numbness was significantly higher than that in patients without lower extremity pain and/or numbness. The incidence of lower extremity pain and/or numbness after laparoscopic colorectal surgery was comparable to that after robot-assisted laparoscopic radical prostatectomy. Prolonged duration of surgery contributed to lower extremity pain and/or numbness. Significantly elevated CK levels in patients with lower extremity pain and/or numbness suggest the involvement of muscle injury in these symptoms.