Electronic nursing documentation constitutes technical, scientific, legal, and ethical documents. The objective of this study was to develop an electronic nursing documentation system. The system was developed in four phases (conceptualization, detailing, prototype building, implementation), and the knowledge base was based on domains and classes according to the NANDA-I, NIC, and NOC unified framework. The result is an electronic system (PROCEnf--USP--Nursing Process Electronic Documentation System of the University of São Paulo) which allows documenting nursing process generating reports of nursing process, besides supporting decisions on nursing diagnosis, expected outcomes, and interventions. Integration of different fields of knowledge, as well as the institutional feature of valuing continuous theoretical and practical improvement of nursing process were factors of success of this technological project.