Depleted uranium (DU) ammunition was used in the years 1994-95 during the conflict in Bosnia and Herzegovina. Following on from previous UNEP field studies in Kosovo (2001, ISBN 0119869667) and in Serbia and Montenegro (2002, ISBN 9280721461), this report assesses the presence and extent of DU contamination in 14 sites investigated in Bosnia and Herzegovina, the corresponding risks to the environment, and possible mitigating actions. DU could easily be found at three of the sites investigated, confirmed by the physical presence of penetrators and jackets, as well as by soil, bio-indicator and air samples. For the first time in UNEP's studies of DU contamination in the Balkans, DU was also found in drinking water samples, albeit at extremely low levels, as well as in air samples taken from buildings currently in use. The report recommends precautionary decontamination and clean-up measures. Given the remaining scientific uncertainties on the long-term behaviour of DU in the natural environment, it calls for further studies to be done in other regions where DU ammunition has been used.