Tigecycline has in vitro activity against multidrug-resistant and extensively drug-resistant Acinetobacter baumannii (MDR/XDRAB), and may constitute an alternative therapy for treating pneumonia caused by MDR/XDRAB. The aim of this study was to compare the efficacy of tigecycline-based therapy with colistin-based therapy in patients with MDR/XDRAB pneumonia. Between January 2009 and December 2010, patients in the intensive care unit who were diagnosed with MDR/XDRAB pneumonia and treated with either tigecycline or colistin mono-/combination therapy were reviewed. A total of 70 patients were included in our analysis. Among them, 30 patients received tigecycline-based therapy, and 40 patients received colistin-based therapy. Baseline characteristics were similar in the two groups. Clinical success rate was 47% in the tigecycline group and 48% in the colistin group (P = 0.95). There were no differences between the groups with regard to other clinical outcomes, with the exception that nephrotoxicity was observed only in the colistin group (0% vs. 20%; P = 0.009). Clinical and microbiological success rates were numerically higher, and mortality rates were numerically lower in combination therapy group than in the monotherapy group. Multivariate analysis indicated that monotherapy was independently associated with increased clinical failure (aOR, 3.96; 95% CI, 1.03-15.26; P = 0.046). Our results suggest that tigecycline-based therapy was tolerable and the clinical outcome was comparable to that of colistin-based therapy for patients with MDR/XDRAB pneumonia. In addition, combination therapy may be more useful than monotherapy in treatment of MDR/XDRAB pneumonia.