The aim of the study was to determine the effect of acetylene block on the emission of nitrous oxide from soils. The study was conducted on three arable soils of Poland: Haplic Podsol - sandy loam, Eutric Cambisol - loess, and Eutric Cambisol - sandy loam, which differ in the initial concentrations of nitrates: 22, 93 and 52 kg N-NO3- ha-1, respectively. The study was performed with natural samples and enriched with two doses of nitrates (100 and 200 kg N- NO3- ha-1) in treatments with and without acetylene block. It was found that N2O emission without acetylene block was on the level of 0-100% as compared to the emission from samples with acetylene block. The effect of acetylene block was more effective in the soils without nitrate amendment.