Background: Acinetobacter calcoaceticus-baumannii complex (Acb) is recognized as an important cause of nosocomial infections. Although Acb can be associated with multidrug resistance, its impact on mortality in burn patients has not been fully elucidated. Study design: In a retrospective cohort study assessing medical records and microbiology laboratory data at a US military tertiary care burn center, we evaluated all patients admitted to the burn center between January 2003 and November 2005. Data collected included age, severity of burn, comorbidities, length of stay, and survival to hospital discharge. In addition, microbiology data were reviewed to determine which patients were infected with Acb during this time frame. These data were then used to compare patients infected with Acb to patients not infected. Multivariate analysis using logistic regression was performed to determine which patient characteristics were associated with increased mortality. Results: There were 802 patients included in the study. Fifty-nine patients met the case definition for infection. An additional 52 patients were found to be colonized with Acb. Patients with Acb infection had more severe burns and comorbidities, and had longer lengths of stay compared with patients without Acb or those with Acb colonization. Mortality in infected patients was higher compared with those without infection (relative risk = 2.86, p = 0.001). On multivariate analysis, infection with Acb was not statistically associated with mortality. Conclusions: Multidrug-resistant Acb is a common cause of nosocomial infection in the burn patient population. Despite this, it does not independently affect mortality.