A simple and sensitive method has been developed for the analysis of residue amounts of chloroacetic acids in betaine samples based on derivatization by 1-naphthylamine (NA). The derivatized compounds are analyzed by reverse phase high performance liquid chromatography using methanol and water as mobile phase in the ratio of 32/68 (v/v) and phenyl column and PDA detection at 222nm. The detection limits (LOD) of monochloroacetic acid (MCA) and dichloroacetic acid (DCA) are 0.1 and 0.15mugmL(-1), respectively. The limits of quantification (LOQ) and the linear dynamic ranges (LDR) of MCA are found to be 1 and 1-400mugmL(-1), respectively, and for DCA are found to be 3 and 3-400mugmL(-1), respectively. The precision at the 5ppm level for MCA and DCA are about 3% and 2%, (n=5), respectively. The average recovery for MCA and DCA spiked to betaine samples are 98% and 97%, respectively.