The aim of the field experiment conducted in the years 2014-2016 at the Plant Breeding and Acclimatisation Institute, Department at Jadwisin, was to determine the potato tuber yield and the uptake and utilisation of nitrogen from the fertilizer Azoslow with slow release of nitrogen, in comparison to conventional nitrogen fertilisers (Urea, Ammonium nitrate, Nitro-chalk). The study was conducted on soil fertilized organically with straw and an intercrop of white mustard. In this experiment a constant level of nitrogen 100 kg N ha–1, phosphorus 17.5 kg P ha–1 and potassium 99.6 kg K ha–1 was used. Mineral fertilisation with phosphorus and potassium was applied in the autumn under ploughing. Mineral fertilisation with nitrogen was applied in the spring in two variants: before planting of tubers – 100%, and a divided dose – 50% before planting of tubers + 50% just before the emergence of potato plants. The control was the treatment without the use of mineral nitrogen. In the treatment with the application of the fertiliser Azoslow, with slow release of nitrogen, a significantly higher yield of tubers was noted compared to the control treatment and in the treatments with Ammonium nitrate and Nitro-chalk. After applying the fertilisers in the full dose before the planting of tubers a significantly higher production efficiency of nitrogen was observed in relation to the dose divided into two parts. Significantly greater nitrogen utilisation by potato tubers was found after the application of the fertilizer Azoslow, compared to Urea, Ammonium nitrate and Nitro-chalk.