A sensitive capillary electrophoresis method has be en developed and optimized for the determination of various organic acid present in the pharmaceutical drug sub stances. The organic acids under study are Formic a cid, Succinic acid, Methanesulfonic acid, Acetic acid, T rifluoro acetic acid and Pivalic acid. These organi c acids are potential impurities in various drug substances and causes undesirable by product. The method was de veloped in such a way that to enhance the detection by employi ng an indirect UV-mode, and minimizing acquisition time by using suitable electrolyte of potassium phthalate a nd flow modifier Cetylammonium bromide in water. To prove the performance characteristic of the optimized method, the study was extended toward validation parameter s as per the ICH guideline requirement for selectivity, sens itivity (limit of detection and quantification), li nearity, precision, robustness, and accuracy. The limit of detection an d limit of quantification for the six organic acids were found to be in between 1.6 and 2.6 μ g/mL and 4.9 and 7.8 μ g/mL respectively.