Aim of the paper was to compare the effects of two very similar fertilisers on nitrous oxide (N2O) flux from soil to the atmosphere in laboratory conditions. There were used following fertilisers: granulated nitrogenous fertiliser DASA® 26/13 with content of nitrogen is 26 %, content of sulphur is 13 %, and nitrogen fertiliser ENSIN® containing sulphur and nitrification inhibitors dicyandiamide DCD and 1,2,4- triazole (TZ). Both fertilisers are produced by the same manufacturer DUSLO, Inc., Šala, Slovakia. For both fertilisers there were carried -1 out three variants of experiments for equivalent of application rates 0, 250 and 500 kg.ha . The amount of N2O emissions released from soil to the atmosphere was measured by photo-acoustic field gas monitor INNOVA 1412 connected to multipoint sampler INNOVA 1309. The experiments were conducted for 30 days in laboratory conditions. The fertiliser was incorporated into the soil in sampling tubes to a depth of 80 mm after 24-hours measurement. Subsequently, after every 24 hours of measurement, another 48 hours was carried out, and this measuring cycle was repeated 10 times. The results of our experiment have confirmed that the fertiliser application rate and type of used fertiliser have a significant effect on N2O flux and have confirmed the importance of accurate and uniform application of the fertilisers in field conditions in order to eliminate the negative environmental effects.