Abstract A HPLC method was developed and validated to analyze meropenem and vaborbactam simultaneously in murine plasma and saline matrixes. A 60-μL volume of extracted sample was injected onto a 5-μm BDS Phenyl-Hypersil C18 reversed-phase column and analyzed with a UV detector set at 298 nm for the first 4.9 min and switched to 240 nm. The mobile phase contained a mixture of methanol and 25-mM sodium phosphate buffer set at a flow rate of 1.0 mL/min for the 16 min run time. Cefuroxime was used as the internal standard. The standard curves were linear over a range of 0.25–50 μg/mL. The precision and accuracy for 0.25 μg/mL (LLQ) in plasma for both compounds were <4.8% and >98.9%, respectively. Interday and intraday precision and accuracy for all QC plasma samples for both compounds were <6.2% and >95.7%, respectively. This methodology details a reproducible assay for both compounds using a single extraction with good accuracy and precision.