Urine patches from grazed pastures are a major source of nitrous oxide emission. Although it is well-documented that the relative concentration of the nitrogenous urine constituents vary significantly with diet, the effect of these variations on N₂O emissions from urine patches has never been reported. This study was conducted to test whether variations in urine composition lead to significant differences in N₂O emission patterns. Four varieties of artificial urine varying in the relative contribution of the nitrogenous constituents, were applied to undisturbed cores from sandy pasture soil and N₂O fluxes were monitored for 65 days at two moisture treatments. Extra replicates were included for destructive analysis on mineral N concentrations and pH. Urine composition was a significant (p<0.001) factor determining N₂O emissions. An increase in the hippuric acid concentration from 3 to 9% of total N resulted in a significant decline in average N₂O fluxes, from 16.4 to 8.7 μg N₂O -N h^-1 kg soil^-1. Cumulative emissions decreased from 8.4 to 4.4 % of the applied urine-N (p<0.01). Soil NO₃ and NH₄ were also significantly affected by urine composition, both showing a decrease with increased hippuric acid content. pH showed no significant relation with urine composition. Increasing the relative urea concentration with 12% did not significantly affect N₂O emissions. As the inhibitory effect of hippuric acid could only partly be linked to soil mineral N concentrations, we speculate that (breakdown products of) hippuric acid may affect the N₂O/N₂ ratio of denitrification. We conclude that hippuric acid is an important factor influencing N₂O emission. Alternative rationing leading to higher hippuric acid concentrations in urine may provide a possible mitigation strategy.