BBackground: A pressure ulcer, which is also called a pressure injury, is an area of damage to the skin and soft tissue underneath it, usually happening over a bony prominence or soft tissue. Nurses have a major role  in preventing pressure ulcers through effective care and evidence-based practices. Aim of the study: the aim was to assess nurses' knowledge and practices regarding pressure ulcer preventive measures . Research design: The present study utilized a descriptive exploratory research design to attain its objective. setting: The current study was carried out in the critical care units of Sohag University Hospital (pediatric intensive care unit – critical care unit).sampling: A convenient sample of all available nurses(50 nures). Tools: Two tools were used to gather the data,Tool (I):A designed interviewed questionnaire to assess personal demographic characteristics and assess knowledge of nurses about pressure ulcer prevention, Tool (II): Checklist for observations to evaluate nurses' work about pressure ulcer prevention. Results: unsatisfactory overall  knowledge of nurses about (96%) with regard to pressure ulcers and incompetent preventive measures were displayed by most of the nurses (94%) in the study. Conclusion: there was statistical significant positive correlation between the total studied nurses' knowledge and practices regarding pressure ulcers in critically ill children. Recommendations: pediatric nurses must be up to date on the latest prevention through workshops, educational programs, and ongoing in- service training programs for nurses is urgently needed to enhance the application of pressure ulcer prevention practices..