Ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME) are synthetic compounds that are used as gasoline additives in order to reduce emissions from vehicles. In the present study, effects of these compounds were investigated on the dynamics of inorganic N in soil. Therefore, soil samples with different water contents were contaminated with ETBE and TAME, respectively. It could be shown that in the presence of TAME and ETBE, NH (4) (+) -N accumulated; moreover, ETBE addition to soil resulted in increased NO (2) (-) -N concentrations. These results indicated for the first time that ETBE and TAME can affect nitrification in soil. Thus, their impact on soil ecology should be investigated more intensively.