OBJECTIVES: Colectomy is a standard procedure in complicated colonic diverticular disease (DD) including diverticulosis and diverticulitis.  Although laparoscopic colectomy (LC) has demonstrated some clinical advantages over open colectomy (OC), the true financial burden, cost and reimbursement structures between the two surgical procedures remain unclear.  The purpose of this study was to compare patient financial burden, direct surgical costs and reimbursements for OC and LC procedures in DD. METHODS: Nationwide commercial claims database from 2003 through 2007 was used to identify 1,614 patients who had undergone OC (n=1327) or LC (n=287) for DD.   Patient financial burden (defined by out-of-pocket [OOP] costs including co-pay, deductible and coinsurance), direct surgical costs, reimbursements and cost-to-charge ratios for OC and LC were compared using the Student’s t-test and chi-square test where appropriate. RESULTS: OC and LC groups differed with respect to mean age (60 and 64 years, respectively; p<0.001) but did not differ in male/female ratio.  OOP costs were significantly greater for OC ($410 vs. $350 for LC; p<0.001).  Both surgical costs and the reimbursements per case were significantly less for OC ($4231 ± 98 and $1412 ± 35, respectively) than LC ($5246 ± 231 and $1809 ± 80 respectively; both p<0.001).  Cost-to-charge ratios were the same for both surgical procedures (0.38). CONCLUSIONS: This analysis demonstrated that patient financial burden, as assessed by OOP costs, was moderately greater for open colectomy, but the direct costs and reimbursements of OC were significantly lower than LC.  However, low surgical costs may be offset by potential increases in length of hospital stay due to longer recovery time for OC.  Understanding differences in cost structures may be helpful in further investigations of the cost-effectiveness of these two surgical procedures in diverticular disease.