Adequate lymphadenectomy is associated with improved survival in patients who undergo oncologic resection of colorectal cancer and has been identified as a quality metric. Neoadjuvant chemotherapy has been found to be associated with collection of <12 lymph nodes in patients with rectal cancer. The purpose of this study was to evaluate patient and operative risk factors for inadequate lymph node retrieval during oncologic colectomy. The 2014 American College of Surgeons National Surgical Quality Improvement Program Participant Use File data set for oncologic colectomy (n = 9077) was analyzed. Patient- and operation-related factors were assessed by univariate and multivariate regression analyses to determine factors associated with the number of lymph nodes collected. Adequate lymphadenectomy was defined by collection of >12 lymph nodes. Of 9077 patients with a diagnosis of colon cancer who underwent colectomy, a minimum of 12 lymph nodes was harvested in 7897 (87%). Significant factors independently associated with inadequate lymphadenectomy included preoperative chemotherapy, emergent surgery, and T1 tumors (all P < 0.05). A large majority of patients who undergo colectomy for colon cancer have at least 12 lymph nodes collected. Preoperative chemotherapy is a major risk factor for inadequate lymph node retrieval. Recognition of factors associated with inadequate lymphadenectomy may improve colectomy lymph node yield and survival in patients with colon cancer.