A new rapid, simple and reproducible UV spectrophotometric method was developed and validated for the estimation of Naproxen Sodium (NpSd) in bulk and pharmaceutical formulation. The quantification of NpSd was done at 230 nm in methanol and in buffer of pH 6.8 and 9. Beer’s law was obeyed in the concentration range of 4 36 (r = 0.999) in methanol and 5 25 μgmL in buffer of pH 6.8 and 9 (r = 0.988 and 0.997) respectively. The apparent molar absorptivity values were also calculated in all mediums. All parameters according to ICH guideline were tested and validated. The detection and quantitation limits were found to be 0.054, 0.083, 0.073 and 0.181, 0.251, 0.211 μgmL respectively. These methods were applied directly to the analysis of the pharmaceutical tablet preparations (Anex tablet 250 mg). The results demonstrated that the procedure is accurate, precise and reproducible (relative standard deviation < 3%), while being simple, cheap and less time consuming and hence can be suitably applied for the estimation of NpSd in dosage forms and dissolution studies.