Aim: to understand the individualization process of the standardized care plan (SCP) that nurses design for hospitalized patients. Background: to apply the nursing process, it is advisable to use SCP to standardize the diagnosis, planning and evaluation stages. However, the fundamental element of this methodology is the individualization of the care plan. Design: a qualitative study, framed within the constructivist paradigm and applying the Grounded Theory method, in accordance with Strauss and Corbin's approach. Methods: multicentre study. Theoretical sampling with maximum variation will be used. The data collection will consist of: in‐depth individual interviews, participant observation, document analysis, focus group, and the questionnaires for Critical Thinking Assessment in relation to clinical practice and Nursing Competency Assessment for hospital nurses. The qualitative data will be analysed according to the constant comparative method of Strauss and Corbin's Grounded Theory, which involves performing open, axial and selective coding. The questionnaire results will be used to make a qualitative analysis that will consist of a triangulation between the level of critical thinking, level of expertise and record of the individualization process performed by the nurses. This protocol was approved in July 2015. Discussion: by knowing the possible stages used in the individualization of a SCP, together with the elements that facilitate or hinder said individualization and nurses' attitudes and experiences regarding this phenomenon, it could help direct improvement strategies in the standardization and individualization process. In addition to recommendations for teaching and research.