We conducted a case-control study to determine the attributable direct costs of multidrug-resistant Acinetobacter baumannii (MDRAB) in the burn unit of a public teaching hospital. The mean total hospital cost of patients who acquired MDRAB was 98,575 dollars higher than that of control patients who had identical burn severity of illness indices ( P <.01). These data should help infection control practitioners and others determine the cost-effectiveness of specific interventions designed to control this emerging nosocomial pathogen.