As part of an ongoing medical surveillance program for U.S. veterans exposed to depleted uranium (DU), biological monitoring of urine uranium (U) concentrations is offered to any veteran of the Gulf War and those serving in more recent conflicts (post-Gulf War veterans). Since a previous report of surveillance findings in 2004, an improved methodology for determination of the isotopic ratio of U in urine (235U:238U) has been developed and allows for more definitive evaluation of DU exposure. This report updates previous findings.