They investigated the risk factors of multidrug-resistant Acinetobacter baumannii infections in 33 burn patients in a mass burn casualty. The independent variables included sex, burn size, vancomycin, ampicillin/sulbactam, cefazolin, meropenem, third-/fourth-generation cephalosporin, the number of classes of antibiotic used, and the number of days of antibiotic use. Multidrug-resistant A. baumannii infection was the outcome variable. Logistic regressions and structural equation model were used for statistical analysis. The average age was 21.7 years (range, 17-32 years; M = 11 [33%], F = 22 [67%]; mean burn area, 42% of the total body surface area; study period, June 28, 2015 to July 31, 2015). The incidence of infection was 39% (n = 13/33). For every percent increase in burn size, the odds of developing A. baumannii infections increased by 1.1 (P < .05). Similarly, the odds increased by 2.5 in every number increase in the classes of antibiotic used, by 1.2 in everyday increase in the days of antibiotic used, and by 12 in patients treated with vancomycin (P < .05). The correlations of these risk factors were demonstrated in a hypothetical structural equation model (P-value of chi-squared test > .05 and root mean square error of approximation < 0.05) in which burn size was the fundamental risk factor of multidrug-resistant A. baumannii infections. The model did not predict the emergence of multidrug-resistant A. baumannii infections. Conclusively, the risks of multidrug-resistant A. baumannii infections in burns are correlated with burn size, the number of classes of antibiotic used, the number of days of antibiotic use, and the prior use of vancomycin.