A simple chromatographic method for the determination of trace thorium in uranium matrix has been reported after studying the retention behavior of U(VI) and Th(IV) as their 2,6-pyridine dicarboxylic acid (PDCA) complexes on a reversed phase column. The method does not require pre-separation of uranium matrix. A mobile phase consisting of PDCA, KNO3, and HNO3 in 5% methanol was used. A calibration plot was constructed in the presence of uranium matrix (r2 = 0.9978). The precision of the method is 5% at 1 ppm of Th and LOD was obtained at 0.1 ppm (S/N =3). The accuracy of the method was checked by comparing the results with neutron activation analysis.