Moxifloxacin is a fourth-generation antibiotic drug that belongs to the fluoroquinolone family. The fluoroquinolones are quinolones with fluorine at position six of the naphthyridine ring. Previous studies indicate that the presence of fluorine atom in the moxifloxacin (Moxi) structure makes its antibacterial activity effective against both types of gram-positive and gramnegative pathogens. Its clinical studies confirmed that it is a well-tolerated drug and has high efficacy against pneumonia, acute bacterial rhinosinusitis, and chronic bronchitis. Previous study was conducted for the estimation of moxifloxacin in bulk and pharmaceutical formulations by spectrophotometer. Analysis of the Moxifloxacin in human plasmas was also conducted by liquid chromatography-electrospray ionization tandem mass spectrometry. Here, in this study we developed and validated a new, simple, precise, accurate, cost effective and reproducible method for the determination of moxifloxacin in bulk and pharmaceutical formulations by reverse phasehigh pressure liquid chromatography (RP-HPLC) as shown in figure 1. The developed method was validated as per the International Council for Harmonisation (ICH) guideline. 2. Experimental Procedure: