OBJECTIVES: An increasing proportion of coronary artery bypass grafting (CABG) surgery is performed with concomitant valve repair or replacement surgery, and complications related to these procedures can have significant impact on patients and healthcare systems. This study quantifies the incidence and clinical and economic burden of complications associated with CABG, valve and combined (CABG and valve) surgery in the US.  METHODS: Premier Perspective database was used to identify patients having CABG and/or valve surgery between Jan 2008 to Dec 2011. The study complications were postoperative infection, septicemia, postoperative stroke, postoperative adult respiratory distress syndrome, new-onset hemodialysis, reoperation, respiratory complication, cardiac complication, and hemorrhage. Both surgeries and complications were identified by ICD-9 codes. This study investigated (1) overall incidence rate of any study complication, (2) differences in length of stay (LOS), and (3) total inpatient costs for patients with and without complications during index and readmission within 30 days across three procedures. For multivariate adjustments, Gamma-distributed generalized linear model (GLM) and Poisson-distributed GLM models were used.  RESULTS: Of 100,601 patients who underwent CABG alone, 31,903 (31.7%) had any study complications during their index or readmitted stay.  Patients with valve alone or combined surgery had higher incidence of complications: 38.2% and 47.3% (p<0.01 for both), respectively. Complications in CABG incurred additional average LOS of 4.8 days (p<0.01) and additional average hospital cost of $14,699 (p<0.01) over CABG patients not experiencing complications, while complications in valve alone and combined surgery incurred an additional 6.8 days, $23,464 and 6.7 days, $24,985 respectively.   CONCLUSIONS: Results showed complications in CABG and/or valve surgery increase clinical and economic burden by 0.41 to 0.60 times in terms of additional LOS and hospital costs. The burden increases significantly when a patient has combined procedures. The results highlight the potential opportunity for cost reduction by preventing the complications associated with CABG and/or valve surgeries.