"Florence Nightingale, founder of modern nursing in nineteenth century, asserted the nurse‟s role was to assist the nature reparative process. And, while this holds true today, nursing has developed into a profession in its own right with its own unique body of knowledge, scope of practice and educational preparation. This thesis focuses on intensive care nursing practices in two private intensive care units (ICU) in Ciudad de Buenos Aires. Specifically, it explores the knowledge, skills and attitudes critical care nurses require to undertake their practice. An ethnographic approached was used in this study. Twelve critical care nurses, from two private ICUs of Ciudad de Buenos Aires were invited to participate in the study. Both ICUs were considered Level 1 units according to the classification of the Argentine Society of Intensive Care Medicine and the Argentinean Health Ministry, that is they provide services for the most complex patient groups. Four data collection strategies were used: participant observation, a reflective journal, and both formal and short focused interviews. Thematic analyses uncovered five themes that reflect the core of intensive care nursing practices and one theme related to the context. The main themes were gaining competence; assessing, anticipating deterioration, acting; collaborating to provide care; individualizing care; and caring. Argentinian participants acquired their competence through a journey of learning. The journey provide them a „know what‟ and a „know how‟, that is their knowledge and skills. ICU nurses learn by repetitive exposure to clinical situations, from their peers and other practitioners. The knowledge and skills they acquired developed and mutated. They have understanding that lifelong learning was vital to their performance in intensive care. Experience helped nurses to perform intuitively. A significant skill was the ability of nurses to assess, anticipate deterioration and act in smooth, continuous fashion. Assessment allowed nurses to identify signs of clinical deterioration and respond appropriately in a timely manner. The patient‟s clinical condition was a driverof nursing actions. Nurses were able to perform collaboratively. They understood their contribution to the team in terms of effective communication and understanding. Caring attitudes were also uncovered. Participants made efforts to identify and meet patient particular needs. They tried to recognize the patient as whole and connect with the patient. Participants also provided compassionate care. They could understand patient suffer, even though it was difficult for them. They empathized with the patient. Sometimes they couldn‟t be compassionate; as a result detachment was evident. However they acknowledged their difficulty to balance detachment and compassion. Finally, intensive care nursing practice was influenced by the context and by some nurses‟ personal characteristics. Understanding intensive care nursing practice is important for many reasons. First, it may inform future postgraduate education in the specialty of intensive care nursing. Second, it may guide in-service training. Third, it may assist managers in recruitment intensive care nurses. Lastly, it may serve as a foundation for future certification processes. While these findings provide a beginning understanding of intensive care nursing practices in Argentina; they highlight many issues for further inquiry. Additionally, this study provides a view of the gap between intensive care practice in Argentina and its counterpart in developed countries. Thus, it also helps to envision future developments of intensive care nursing as discipline in Argentina."