New, simple and rapid method indicating UV spectroscopy was developed and validated for the estimation of Indomethacin(IND)in pure form, and in respective formulations. (0.1N) KOH solution was used as a solvent to decompose IND to p-Chlorobenzoic acid and 5-methoxy-2-methyl-3-indoleacetic acid .The adequate drug solubility and maximum assay sensitivity was found asp-Chlorobenzoic acid, the maximum absorbance of p-Chlorobenzoic acid was measured at (228nm)in the wavelength range of (200‐650 nm), the linear calibration curve was obeyed in the concentration range of (1-10 ppm)show regression equation (Y =0.1263X -0.002), and correlation Coefficient (R2=0.9949). This method was validated and applied to the determination of IND in capsules from different companies in Iraqi market, no interference was found from capsule excipients at the selected wavelength and analysis conditions. It was concluded that the developed method is accurate, sensitive, precise, and reproducible; as well as itcan be applied directly for the estimation of p-Chlorobenzoic acid and indirectly for the estimation of IND content in pharmaceutical formulations.