Making the transition to an area of specialist nursing practice is challenging for both the learner and staff who are responsible for education and skill development. This study uses grounded theory methodology to explore the question: "How do nurses learn critical care nursing?"The eight registered nurses who participated in this study were recruited from a range of intensive care settings. The criteria for inclusion in the study included the participant having attained competency within the critical care setting. Data was collected from individual interviews. The findings of this study developed during the coding and comparative analysis process, and subsequently theoretical sampling was used to further explore the identified concepts.This study found that nurses' focus on two main areas during their orientation and induction into critical care nursing practice. These are learning to do (skill acquisition) and learning to be (professional socialisation). The process of transition involves two stages: that of learning to do the tasks related to critical care nursing practice, and the ongoing development of competence and confidence in practice ability. The relationship of the learner with the critical care team is a vital part of the transition to competency within the specialist area.This study identifies factors that influence the learner during transition and also provides an understanding of the strategies used by the learners to attain competency. These findings are applicable to educators and leaders responsible for the education and ongoing learning of nurses within critical care practice. The use of strategies such as simulated learning and repetition are significant in skill acquisition. However attention must also be paid to issues which influence the professional socialisation process, such as the quality of preceptor input during orientation and the use of ongoing mentoring of the learner.