The concept of oxidation state (or oxidation number) and related issues have always been difficult for students. In addition, there are misunderstandings and obscurities, which can cause improper balancing of the chemical equations (mostly in organic reactions). In particular, these problems are related to determination of the oxidation state of nitrogen and carbon atoms in organic compounds. In recent years, the Matura Exam in Poland (ending education in Upper Secondary School) puts special emphasis on verification of students' skills of balancing of chemical equations on examples of organic compounds. In the absence of literature, methods and rules for establishing or assigning the oxidation state to nitrogen atoms in organic compounds, the authors decided to emphasize this undoubtedly important problem in this article. We present here, various approaches to determination of the oxidation state to nitrogen and carbon atoms in organic compounds. Additionally, we propose an alternative approach to determination of the oxidation state to nitrogen atoms in complicated situations ("nitrogen oxidation state trick"). Moreover, on the basis of results of our didactic studies, we indicate which method is the most popular and the best assimilable among Polish students from Upper Secondary School.