The research results presented concern the effect of varied nitrogen fertilization (60, 120, 180 kg ha-1 ) in the cultivation of Chenopodium quinoa on selected chemical properties of soil (organic carbon, total nitrogen, ammonium nitrogen, nitrate nitrogen, magnesium, phosphorus, potassium and pH). The research was carried out on Luvisol, on light silty loam, at the Experimental Station for Cultivar Testing at Chrząstowo in the Kujawy and Pomorze Province over the period of 1998-2001. The content of basic nutrients of was analysed soil prior to the cultivation and after harvest of Chenopodium quinoa grown for seed, where additionally manure was used, and when cultivated for green matter without manure. It was observed that after the cultivation of Chenopodium quinoa the values of most chemical components of soil were higher, which demonstrates positive trends of changes in the chemical properties of soil after the cultivation of Chenopodium quinoa. The use of nitrogen at doses of 60-180 kg ha-1 with manure in the cultivation of Chenopodium quinoa stimulated similar chemical properties of soil. Positive trends of changes were observed. The greatest similarity of chemical properties of soil in the cultivation without manure was found after the application of the doses of 60 and 120 kg ha-1 of nitrogen; they also stimulated positive trends of changes. The dose of 180 kg ha-1 of nitrogen without manure used in the cultivation of Chenopodium quinoa resulted in a decrease in the values of most chemical properties.