This is a theoretical analysis of Constructivist Grounded Theory and its application in nursing research. It is organized in three topics: Characteristics of Grounded Theory; Philosophical basis of the constructivist strand; and Constructivist Grounded Theory data analysis particularities. The unique characteristics of Grounded Theory that set it apart from other approaches are simultaneous data collection and analyses, theoretical sampling, constant comparison at each stage of analysis, development of memos for reflexive and comparative analysis, and a coding system with an initial and a focused stage that is flexible and guides the analytical process of building a theory. Before embarking on a Constructivist Grounded Theory study, the literature is reviewed to hone the research question. The philosophical assumptions of symbolic interactionism and social constructivism influence the entire process. Constructivist Grounded Theory emphasizes the construction and interpretation of data recognizing social contexts, interaction, the point of view of participants, and their understandings according to the investigation time, place and situation.