Background. The Neutrophil-to-Lymphocyte Ratio (NLR) is an inflammatory marker that has proven usefulness for predicting late complications. Whether it is associated with immediate postoperative complications after abdominal surgery is not known. In this study, we attempted to correlate the NLR and the C-reactive protein (CRP) with postoperative complications rate. Methods. We performed a post-hoc analysis of previously collected data concerning 82 consecutive patients (median age: 62 years, range: 27–80, female/male 32/50) undergoing major abdominal surgeries. For each patient, we recorded preoperative characteristics, the NLR and CRP values, and postoperative complications (between D + 8 and D + 30) such as infections (N = 29), cardiovascular complications (N = 12) and other complications (N = 28). We performed uni- and multivariate analyses using logistic/linear regression models. Results. Patients with complications did not present a higher preoperative NLR than those without, but a higher ratio at D + 7 (10.73 ± 9.86 vs. 4.73 ± 3.38 without complication) (P < 0.001). In the univariate analysis, the NLR at D + 7 was associated with postoperative complications (P < 0.001). At D + 7, in the multivariate analysis, an increased NLR was associated with more complications (P < 0.001), whereas none of the other factors, including CRP, showed any correlation. Conclusion. Postoperative NLR at day 7 after major abdominal surgery is associated with complications during the first postsurgical month, in contrast with the CRP level. The NLR is a simple and interesting parameter in the perioperative period.