Introduction: Among military personnel with complex battlefield-related injuries, infections are common. Prior analysis showed that combat casualties with infections attributed to multidrug-resistant gram-negative (MDRGN) bacilli had increased inpatient resource utilization (e.g., hospital length of stay [LOS]) compared to those with non-MDRGN infections (non-MDRGN-I). We examined the total inpatient hospital cost for combat casualties who developed MDRGN infections (MDRGN-I) compared to those with non-MDRGN-Is. Methods: This was a cross-sectional retrospective study on military personnel wounded during deployment (6/2009-12/2014) admitted to Landstuhl Regional Medical Center (LRMC) and subsequently transferred to participating U.S. military hospitals. Total inpatient cost was compared between patients with MDRGN-Is and non-MDRGN-Is. Covariates assessed included factors associated with injury characteristics (e.g., pattern, severity, and mechanism), early trauma care, inpatient infections, ICU admission, LOS (inpatient and ICU), mechanical ventilation, chest tube, central venous catheter (CVC), clinical cultures, operating room (OR) visits ≤2 weeks post-injury, directed antibiotics, and provider types. Chi-square, Fisher’s exact, or Wilcoxon rank-sum tests assessed differences in covariates between infection groups. Linear regression models assessed unadjusted and independent associations with cost. All covariates significant in unadjusted models were considered for inclusion in the adjusted model. The significance threshold was P<0.05. Results: Among 476 combat casualties with infections, 148 (31%) had MDRGN-Is and 328 (69%) had non-MDRGN-Is. Patients were primarily young (median age at injury: 24 years) males (99%) who served in the U.S. Army (66%) and sustained blast-related injuries (82%) in Afghanistan (95%). Median inpatient LOS was 60 days (4 at LRMC, 56 at U.S. hospitals) for individuals with MDRGN-Is and 43 days (4 at LRMC, 39 at U.S. hospitals) for individuals with non-MDRGN-Is. Total inpatient cost for MDRGN-I individuals was significantly higher than non-MDRGN-I individuals (6,394 versus 5,777, P<0.001). The final adjusted model revealed independent associations with increased total cost for lower extremity injury (effect size 1.18, 95% CI 1.07-1.30), head/face/neck injury (1.23, 1.11-1.35), pneumonia (1.24, 1.13-1.36), LRMC ICU LOS (1.04, 1.02-1.05), U.S. hospital ICU admission (1.18, 1.07-1.29), CVC use (1.17, 1.05-1.30), U.S. hospital LOS (1.01, 1.01-1.01), and OR visits (1.06, 1.04-1.09). Having a MDRGN-I was not independently associated with higher cost in the final model (1.02, 0.94-1.12). When considering factors associated with higher cost, individuals with MDRGN-Is had significantly more lower extremity injuries (85% versus 72%, P=0.002), pneumonia (37% versus 25%, P=0.010), U.S. hospital ICU admissions (77% versus 59%, P<0.001), CVC use (91% versus 71%, P<0.001), and OR visits (median 5 versus 4, P<0.001), as well as longer LRMC ICU LOS (median 3 versus 2 days, P<0.001) and U.S. hospital inpatient LOS (median 56 versus 39 days, P<0.001) compared to individuals with non-MDRGN-Is. Discussion: Although individuals with MDRGN-Is had significantly higher median inpatient costs than those with non-MDRGN-Is, having a MDRGN-I was not independently associated with higher cost. Nevertheless, individuals with MDRGN-Is had significantly higher utilization of most factors independently associated with higher cost (pneumonia, ICU admission and LOS, CVC use, U.S. hospital inpatient LOS, and OR visits). Overall, increased inpatient resource utilization translated into significantly higher total inpatient hospitalization costs among combat casualties.