The paper presents nitrogen balance in 97 selected agricultural farms in Kobylin commune. The studies included the following factors: cattle stock size, nitrogen production in natural fertilizers and nitrogen balance in the farms. It was found that in the studied farms, the size of cattle stock was high (in 63% of farms, it amounted from 1 to 2 large livestock unit). Only in 5 farms, the nitrogen balance was negative: in 27% of farms, it did not exceed 30 kg, while in 25% of farms, it was from 60 to 100 kg N/ha. In two farms, nitrogen surplus in natural fertilizers was very high amounting to 387,4 and 415,8 kg N/ha. Fertilization with nitrogen in natural fertilizers was increasing with the number of animals. The increasing nitrogen fertilization by natural fertilizers limited N fertilization in the mineral form, but only in a small degree.