Urine certified reference material (CRM) has been developed to help clinical labolatories control analytical accuracy. Two levels of freeze-dried urine were prepared. The low level CRM was made from normal urine and the abnormal level CRM was prepared by spiking the normal urine with As, Cd, Cr, Cu, Hg, Ni and Pb. Urine reference materials were analyzed by graphite furnace atomic absorption spectrometry (GFAAS) and inductively coupled plasma mass spectrometry (ICP-MS) . Analyte elements were separated from matrix elements by using ion exchange resin and hydride generation. Isotope dilution method was employed to enhance analytical accuracy. Round robin test results are also presented which were carried out with 5 clinical laboratories.