Objectives: Validation of an online course content on postural care for newborns in the Neonatal Intensive Care Unit and assessment of participant satisfaction. Method: Methodological study of content validation by 13 judges with expertise in neonatology and online education who responded to the educational content validation instrument, and by 175 course participants who evaluated the course through a satisfaction questionnaire. The criterion for validation was agreement above 80.0%, analyzed through the Content Validity Index (CVI), Content Validation Coefficient (CVC), binomial test, and descriptive statistics for analyzing satisfaction variables. Data collection took place from January to June 2022 for the validation stage, and during June 2023 for the evaluation stage conducted by the course participants. Results: All items obtained agreement above 80.0% with a total CVI and CVC of 83.3% and 91.0%, respectively. The course participants positively evaluated the course regarding content organization, coherence between theory and practice, navigability, quality of materials, and applicability in professional practice. Conclusion: The online course was considered valid regarding its objectives, structure/presentation, and relevance. Therefore, it can be offered as an open educational resource in the training of healthcare and nursing professionals to provide postural care to newborns in critical environments, thereby enhancing the performance of developmental care.