Purpose: The purpose of the study was to evaluate the usefulness of the triggering receptor expressed on myeloid cell 1 (TREM-1) protein as a marker for serious infectious complications during laparoscopic colorectal surgery. Methods: Sixty-four patients with colon or rectal cancer, who underwent an elective laparoscopic colorectal cancer surgery from November 2018 to February 2020, were included in the analysis. Blood samples of the TREM-1 protein testing were collected four times from each patient: before and on three following postoperative days (PODs). Patients were divided into two groups according to the presence of infectious complications. Subsequently, patients with infectious complications (group 1) were matched 1:1 with patients without complications (group 2). The case-matched analysis was done by selecting patients from the control group by age, ASA scale, cancer stage, and type of surgery. Results: There was no significant difference in demographic and operative characteristics between the two groups. The median length of hospital stay was longer in group 1 than in group 2 (11 days vs. 5 days, p < 0.001). Preoperative measurements of TREM-1 protein did not differ between the two groups. There were no significant differences in the measurements on the first and third postoperative days. However, the median TREM-1 measurement was higher in group 1 on the second postoperative day (542 pg/ml vs. 399 pg/ml; p = 0.040). The difference was more apparent when only severe postoperative complications were considered. When compared to the group without any complications, the median TREM-1 level was significantly higher in the group with severe infection complications in POD 1, POD 2, and POD 3 (p < 0.05). The receiver operating characteristic (ROC) curve demonstrated that TREM-1 readings in POD 2 had a sensitivity of 83% and a specificity of 84% for the presence of severe infection complications at a value of 579.3 pg/ml (AUC 0.8, 95%CI 0.65–0.96).