Recently, it was reported that amoxicillin-clavulanate has slightly higher activity than amoxicillin against Helicobacter pylori. In this study, we evaluated the in-vitro antibacterial activity of beta-lactamase inhibitors against H. pylori. We investigated the susceptibility of 30 H. pylori strains to beta-lactamase inhibitors, including clavulanate, sulbactam, and tazobactam. In short-term bactericidal studies, a clinical isolate of H. pylori NU27 was exposed to 1 x minimum inhibitory concentration (MIC) of the beta-lactamase inhibitors, amoxicillin, clarithromycin, and amoxicillin-clavulanate for 3 and 6 h. The MICs90 for these beta-lactamase inhibitors were 2, 4, and 2 mg/l, respectively. The short-term bactericidal studies showed that these beta-lactamase inhibitors decreased viable counts of H. pylori during 6-h exposure at 1 x MIC. Our results suggest that beta-lactamase inhibitors have in-vitro antibacterial activity against H. pylori. Amoxicillin and clavulanate used in combination resulted in increased antibacterial activity.