Ampicillin/Sulbactam is a combination of antibiotics made up of ampicillin, a betalactam and Sulbactam, a betalactamase inhibitor introduced in the eighties. The most frequent used combination is Ampicillin/Sulbactam (ratio 2:1) although the two agents are not synergetic. Ampicillin/Sulbactam has a wide range of antibacterial activity that includes Gram-positive and Gram-negative aerobic and anaerobic bacteria. However, the drug is not active against Pseudomonas aeruginosa and pathogens producing extended-spectrum β-lactamases. The combination could be considered particularly active against Acinetobacter baumannii infections due to the intrinsic activity of Sulbactam. In clinical trials, sultamicillin has proved clinically and bacteriologically effective against a severe bacterial infections, including mild upper and lower respiratory tract infections, meningitis, intra-abdominal, diabetic foot and skin and soft tissue infections, etc. Furthermore, adverse effects rarely occur with the diarrhoea to represent the most commonly reported. Moreover, it seems to represent the alternative of choice for the treatment of A. baumannii infections for carbapenem-resistant strains in the nosocomial setting. This review focuses on the efficacy of the β-lactam ampicillin co-administered with the β-lactamase inhibitor sulbactam, parenterally (Ampicillin/Sulbactam), for the treatment of bacterial infections.