A grounded theory method was used to study nurses' clinical decision making. Field notes, in-depth interviews, and documents were analyzed. The beginning process model contained the core concept, knowing the patient, a purposeful action whereby the nurse uses understanding of the patient's experiences, behaviors, feelings, and/or perceptions to select individualized interventions. Familiarity and intimacy were the properties of the core process; the patient-nurse interaction was the context. Three conditions included time, the nurse's experience, and other nurses' input. Four strategies facilitated the core process: empathizing, matching a pattern, developing a bigger picture, and balancing preferences with difficulties. Different strategies were used, as time and familiarity with the patient varied.