Background: Decision-making is a risk factor for the physical and mental health of parents of children hospitalized in the pediatric critical care unit (PICU). Here we present a situation-specific theory that seeks to support and guide the nurses' actions so that they can include the parents in their care plans, thus facilitating their participation in decision-making. In this way, not only will better decisions be made, but parents will cope better with the negative consequences of the stress they have experienced. Aims: To describe a theory developed to guide nursing practice in the PICU, particularly regarding parental participation in decision-making for hospitalized children. Methods: Methods: Following the integrative strategy, a situation-specific theory was developed from the analysis, ordering, and grouping of data extracted from (i) the research and practice, (ii) theories related to the phenomenon of interest, and (iii) the systematic review of the literature. Results: The results obtained were condensed into five concepts that were used to create the abstract representation of the phenomenon studied and to elaborate and defined a theory that describes parental participation in decision-making about the hospitalized child in the PICU: The Krisis theory. Conclusions: To make parental participation in decision-making helpful and satisfactory for both the parents physical and mental health as well as the child's, this theory considers five concepts: effective communication, steady interactions with the nurse, the recognition of the parents' needs, their recognition as fundamental actors in the process, and (v) an adapted context for the care of the child and family. Keywords: Nursing theory, Decision-making, pediatric intensive care unit, Parents, Nursing care