The prognostic nutritional index (PNI) has been correlated with long-term outcomes in cancer patients. However, the relationship between PNI, the postoperative complications, and long-term outcomes in patients with colorectal cancer (CRC) undergoing curative laparoscopic surgery has not been fully investigated. This retrospective study was conducted in the Beijing Hospital between January 2009 and January 2012. A total of 228 patients diagnosed with primary CRC undergoing curative laparoscopic surgery in the center were analyzed. The last follow-up date was December 2015. The associations of the PNI status with postoperative outcomes were examined using univariate and multivariate analyses. The optimal cutoff value of the preoperative PNI was set at 44.55 using the receiver operating characteristic curve. The patients were classified into PNI-high (≥44.55) and PNI-low groups (<44.55). The patients in the PNI-low group were more likely to have increased levels of tumor markers such as carcinoembryonic antigen and carbohydrate antigen 19-9, aggressive histological features, advanced tumor-nodes-metastasis (TNM) stages (all P < 0.05). Multivariate analyses revealed PNI<44.55 as an independent factor associated with the incidence of severe postoperative complications and overall survival. In conclusion, for patients with CRC undergoing curative laparoscopic surgery, PNI is a valuable biomarker in preoperative estimation as well as prognosis prediction.