The aim of this study is to evaluate the efficacy of using Ampicillin-Sulbactam (AS) for treatment of septicemia, caused by multi-resistant strains of Acinetobacter baumannii (AB), in burn patients. Forty patients were included in the analysis over 2003. Cultures were performed on blood samples taken from these patients. Sensitivity of the strains to Ampicillin-Sulbactam was determined, marking the zones of inhibited growth and determining the Minimal Inhibitory Concentration (MIC) by using the BIOMIC system. AB strains in 24/40 patients were shown to be completely resistant to AS. In 10/40 or 25% of cases the isolate demonstrated medium sensitivity to AS, whereas in only 6/40 or 15% of the patients this strain proved to be completely AS-sensitive. 29/40 Patients were subjected to AS therapy. 16/29 Patients had an AB strain resistant to AS whereas 13/29 Patients showed medium or complete AS sensitivity. These 29 patients were all treated with a maximum daily dose of 3 grams of AS every six hours. Eradication of AB from the wound bed, after completing the full course, was achieved in 20/29 patients, who fully recovered. This included 9/29 patients that demonstrated in-vitro AS resistance. In 7/29 patients, despite the completed AS course with a maximum daily dose, a sterile blood culture and eradication of AB from the wound bed was not achieved. These patients died as a consequence.