OBJECTIVES: The cost of colectomy may vary widely; however, an understanding of factors contributing to this variation is still limited.  In this study total hospital costs were compared between open (OC), laparoscopic (LC), and robotic-assisted colectomies (RC).  Factors associated with differences in hospital costs across different surgical approaches were explored.  METHODS: All adults undergoing colectomy and discharged between January 1, 2010 and December 31, 2014 were identified in the Premier Healthcare Database (PHD).  PHD contains approximately 20% of all US hospital discharges.  Patients were grouped by the surgical approach used: OC, LC, or RC.  OC and LC patients with ICD-9 codes indicating robotic assist on the same hospital day were categorized into the RC group.  Patient and hospital characteristics were compared between surgical approaches and a multivariable regression model was used to assess association between surgical approach and total hospital cost. RESULTS: A total of 125,077 discharges with colectomy were identified (68.2% OC, 29.1% LC, and 2.7% RC).  LC patients were older and more likely to have malignant cancer and less likely to have prior surgical site infection than OC or RC patients (all p<.0001). OC patients had greater severity of illness and risk of mortality as determined by APR-DRG, higher Charlson Comorbidity Index, and longer LOS than LC or RC patients (all p<.0001). Adjusted mean total hospital cost for LC patients ($16,982 ± 6,746) was significantly lower than OC ($25,775 ± 13,168) or RC patients ($20,673 ± 7,203) (p<.0001).   Large variations in hospital cost within an approach were also observed. CONCLUSIONS: After adjustment, total hospital costs were lower for patients with LC versus the other approaches and may support a greater role for the laparoscopic approach if clinical outcomes are also improved.  Further evaluation is needed to identify factors contributing to the variation in hospital cost for each approach.