A simple procedure has been developed for the simultaneous determination of the urinary anthranilic and 3-hydroxyanthranilic acids by gas chromatography. The method is based on extracting from urine with chloroform or ether at pH 3.0, followed by converting to their trifluoroacetyl derivatives. A clear separation of anthranilic and 3-hydroxyanthraniclic acids was achieved by using 3% OV-17 column at 110°. Compared with the recovery values of anthranilic acid, those of 3-hydroxyanthranilic acid are considerably low, which is due to the decomposition of 3-hydroxyanthranilic acid in the extraction procedure.