Aims and objectives: We created and validated a checklist for nursing care of patients in the immediate postoperative period of cardiac surgery. Background: Cardiovascular diseases (CVD) account for about 30% of all deaths recorded in Brazil. There is an arsenal of clinical and surgical treatments for CVD, with a significant number of patients evolving to surgical treatment. Thus, health professionals working in the perioperative period of cardiovascular surgeries need to be updated, trained and qualified to provide adequate and safe care to patients. Design: We developed a checklist that defined essential parameters for quality care, to ensure greater agility and patient safety. Methods: This methodology validation study comprised two stages: checklist creation for care provided by nurses to patients in the IPO of cardiac surgery, and content validation using the Delphi method. Participants were selected through an advanced survey conducted on the Lattes Platform website of the National Council for Scientific and Technological Development. The STROBE checklist was used to guide the study. Results: Three rounds of analysis by specialists resulted in average CVIs of: 95.8% for objectivity, 97.9% for simplicity, 91.0% for clarity, 93.1% for relevance and 96.5% for variety, suggesting high agreement among specialists. Conclusions: The checklist focused on nursing care of patients in the IPO of cardiac surgery and was validated with three topics, four categories, 16 items and 86 subitems of care assignments to be applied in clinical practice. Relevance to clinical practice: This is a validated instrument that guides nurses' actions by admitting postoperative cardiac surgery patients to the ICU based on evidence, which provides more scientific and professional support to health teams' performance, with the objective of strengthening roles and establishing routines; thus presenting a powerful tool for planning nursing actions, providing quality care to patients, and facilitating communication between teams, thereby minimising risks. 4172 | BATISTINI eT Al. 1 | INTRODUC TI ON Cardiovascular diseases (CVD) are responsible for a significant mortality rate on a global scale, especially acute coronary syndrome and heart failure (Pagidipati & Gaziano, 2013; Stewart, Manmathan, & Wilkinson, 2017). Among the set of treatments for CVD, special attention is drawn to clinical and surgical treatments, with high incidence of surgical procedures driven by technological progress and improved techniques used in the field (Furtado et al., 2017). Considering the high complexity involved in the immediate postoperative period (IPO) of cardiac surgery, quality of care becomes the main premise of health assistance, since nurses must identify haemodynamic changes and implement appropriate interventions quickly and effectively, minimising the incidence of errors (Santos,