PURPOSE: Para-aortic lymph node (PALN) metastasis from colorectal cancer is rare and often not suitable for surgery. However, in selected patients, radical resection may bring about longer survival. The aim of this study was to evaluate long-term outcomes of resection of left-sided colon or rectal cancer with simultaneous PALN metastasis. METHODS: The study included 2122 patients with left-sided colon or rectal cancer (30 patients with and 2092 patients without PALN metastasis) who underwent resection with curative intent between 2002 and 2013. Clinicopathological characteristics, long-term outcomes of resection, and factors related to poor postoperative survival in patients with PALN metastasis were investigated. RESULTS: Of a total of 2122 total patients, 16 of 50 patients (32.0%) with lymph node metastasis at the root of the inferior mesenteric artery had PALN metastasis. The 5-year overall survival rates for 18 patients who underwent R0 resection and 12 patients who did not were 29.1 and 10.4%, respectively (p = 0.017). Factors associated with poor postoperative survival among patients who underwent R0 resection were presence of conversion therapy, lack of adjuvant chemotherapy, carcinoembryonic antigen >20 ng/mL, and lateral lymph node metastasis in rectal cancer patients. The 5-year recurrence-free survival rate was 14.8%. CONCLUSIONS: Although recurrence was frequent, R0 resection for left-sided colon or rectal cancer with PALN metastasis was associated with longer survival than R1/R2 resection. Furthermore, the 5-year overall survival rate in the R0 group was relatively favorable for stage IV. Therefore, R0 resection may prolong survival compared with chemotherapy alone in selected patients.