A flow injection analysis (FIA) of Naproxen sodium (NAPS) using UV detection is described in this study. The best solvent system used as a carrier solution was found to be an aqueous solution of EtOH (10% v/v). A flow-rate of 1.2mL min(-1) was used and Naproxen was detected at 230nm. Repeatability was examined using 8 x 10(-6) M NAPS solution and relative standard deviation (RSD) values were found to be about 2.2 for intra-day and inter-day studies. The calibration equation was the linear range of 4 x 10(-6) to 1. 18 x 10(-5) M. Limit of detection (LOD) and limit of quantification (LOQ) were calculated as 5.8 x 10(-7) (S/N = 3.3) and 1.7 x 10(-6) M (S/N = 10), respectively. The proposed method was applied for the detennination of NAPS in pharmaceutical tablet formulation, containing 275 mg active material. The proposed method is reliable, precise, accurate, and rather cost effective, and can be applied for uniformity tests in NAPS tablets.