Introduction: Due to the advancement of the home-based healthcare, increasing the number of professionals who are able to administer homebased treatments, such as endotracheal suctioning, is an urgent issue.Methods: By measuring the ocular movement of nurses, nursing students and previous researches, an endotracheal suctioning ontology was visualized. It included a multiplex task structure, recognition, and judgment, as well as identifying procedures used during endotracheal suctioning that could contribute to a discussion on educational feasibility.Results: From the hierarchical structure of the constructed endotracheal suctioning ontology, not only the procedural knowledge but also knowledge about medical devices, knowing what options exist when endotracheal suctioning is ineffective, and a wide range of other expertise is needed to perform endotracheal suctioning safely.Discussion: An endotracheal suctioning ontology was created from the ocular movement of nurses. Ontologies are a potential tool for defining minimum requirements and the scope of ability that must be evaluated before clinical practicum.