ABSTRACT Objetives: to analyze the ingredients of the competence that the nurses use in the performance of their work in hemotherapy. Methods: qualitative study with 22 nurses, accomplished through documentary study, observation and semi-structured interview, with resources of Atlas.ti software based on the foundations of Historical Materialism Dialectic and Ergology. Performed Content Analysis. Results: the domain of specific knowledge of hemotherapy and the time of experience in the area, allied to the motivation of the worker and the ability to work in a team favor the competent action in the work activities. On the other hand, the lack of adequate work conditions, especially in relation to adequate materials, equipment and structure, impairs the work of the nurse in hemotherapy. Final Considerations: experience gained is critical to successful decision making. In addition, adequate working conditions, updating of knowledge and ability in teamwork favor a scenario of safe practices.