Objective: To describe the factors that influence the emergence of moral distress in oncology nurses. Methodology: integrative review of the literature whose search will be performed in Web of Science databases, CINAHL (EBSCO), Scielo, Proquest, Pubmed and PsycInfo using the keywords moral distress and oncology nursing and their similes in Spanish, without restriction for years of publication until 2017. Results: The results of this review were grouped into three groups of factors each with subgroups: 1) Organizational factors: ethical climate, evasive culture and resources for ethics delivered by the organization. 2) Particular clinical situations: pain management, information delivery, futile treatment, and assistance to the patient and their family in the process of death, 3) Interpersonal relationships: poor communication, power relations, trust in the team’s competence. Conclusion: the three factors described are triggers of moral distress in oncology nurses. When there are ethical problems and the nurses do not participate in the deliberation process, these problems can be hidden and be normalized, which can diminish the moral sensitivity of the professionals, as well as the possibility of acting as moral agents.