Study that had as its object the analysis of knowledge, power and practice in the beginnings of nursing at “Las Mercedes” hospital, in Chiclayo-Peru, whose antecedents go back to the original practices of professional nurses, to the forms of hospital organization and to Nursing. This is a historical-social study, whose temporal cut covers the period from 1960 to 1980. The initial milestone was the insertion of the first professional nurses with university training (1969). The final milestone occurs with the transfer of the hospital to the Ministry of Health (1980). Primary sources were used, consulting newspapers, documents, magazines, institutional archives. Speeches were obtained from six nurses who worked during the time. The theoretical framework was based on Michel Foucault, using his method of discourse analysis. Two empirical categories emerged: Incorporation of professional nursing as a strategy of power in the hospital field, process which required an internal structuring of nursing, establishing a statute of power that delimited the role of nurses; and knowledge/power devices established in nursing practice, such as the micropowers, which originated power networks, between nurses and agents, by means of hierarchical and divided relationships, which originated nursing as a hospital institution. © 2022 Authors. All rights reserved.