: Systemic inflammatory indices have been largely investigated for their potential predictive value in multiple inflammatory, infectious, and oncological diseases; however, their value in colorectal cancer is still a subject of research. This study investigates the dynamics of pre- and postoperative values of NLR, PLR, SII, and MLR in patients with colorectal cancer and their predictive value for early postoperative outcomes. : A 2-year retrospective cohort study was performed on 200 patients operated for colorectal adenocarcinoma. Systemic inflammatory indices were calculated based on complete blood count preoperatively and on the first and sixth postoperative days. The patients were divided into two groups based on their emergency or elective presentation. The pre- and postoperative values of serum inflammatory biomarkers and their correlations with postoperative outcomes were separately analyzed for the two study subgroups. : There were no significant differences in sex distribution, addressability, associated comorbidities, or types of surgery between the two groups. Patients in the emergency group presented higher preoperative and postoperative values of WBC, neutrophils, NLR, and SII compared to elective patients. The postsurgery hospital stays correlated well with pre- and postoperative day one and day six values of NLR ( = 0.001; 0.02; and <0.001), PLR ( < 0.001), SII ( = 0.037; <0.001; <0.001), and MLR ( = 0.002; = 0.002; <0.001). In a multivariate analysis, reintervention risk was higher for emergency presentation and anemia, and lower in right colon cancer. In the emergency group, a multivariate model including age, MLR PO1, and pTNM stage was predictive for severe postoperative complications (AUC ROC 0.818). First-day postoperative inflammatory indices correlated well with sepsis, with the best predictive value being observed for the first postoperative day NLR (AUC 0.836; sensibility 88.8%; specificity 66.7%) and SII (AUC 0.796; sensitivity 66.6%; specificity 90%). For elective patients, the first postoperative day PLR and anemia were included in a multivariate model to predict Clavien-Dindo complications graded 3 or more (AUC ROC 0.818) and reintervention (AUC ROC 0.796). : Easy-to-calculate and inexpensive systemic inflammatory biomarkers could be useful in predicting early postoperative outcomes in colorectal cancer for both elective and emergency surgery.