Introduction: Cardiorespiratory arrest is a clinical situation characterized by the interruption of blood circulation. It is estimated that 11.1% of all live births in the world are premature, generating short and long-term repercussions. One of the main challenges during cardiacarrest in premature infants is providing sufficient, but not excessive, oxygen during assisted ventilation. Objective: To compare the effectiveness and safety of using room air in relation to 100% oxygen in the resuscitation of premature infants in cardiorespiratory arrest. Methods: To this end, we will carry out a systematic review of randomized clinical trials (RCTs). The study protocol was registered on the Prospero Platform (CRD42024519724). We will include preterm infants with gestational age <37 weeks with CA. The searches were carried out in the following databases: Medical Literature Analysis and Retrieval System Online (MEDLINE) via Pubmed, Excerpta Médica dataBASE (Embase) via Elsevier, Cochrane Central Register of Controlled Trials (CENTRAL) via Cochrane Library, Latin American Literature and the Caribbean Doctor in Health Sciences (LILACS) through the Virtual Health Library Portal, without restrictions on language or year of publication. The selection of studies, transmission of data, assessment of the bias of included studies and assessment of the certainty of the evidence will be carried out by two independent investigators. Expected results: Clarify the transit and safety of using room air compared to 100% oxygen, provide useful information for clinical decision-making, and support future high-quality randomized clinical trials on the topic. Conclusion: This study aims to compile existing research to analyze the effectiveness and safety of application of 100% oxygen in the resuscitation of premature infants. Keywords: Heart arrest; infant premature; systematic review.