Since the introduction of Western concept of nursing to Korea in late 1880s, Korean nursing practice has evolved into Korean culture. The purpose of this study was to explore and identify similarities and differences in hospital nursing practice between Korea and the United States using the grounded theory method. The data were gathered from 15 Korean nurses working in U.S. hospitals using semi-structured, in-depth interview method. Major similarities in nursing practice between Korea and U.S. existed in the 7 domains the Benner indicated in 1984. The nursing administration system was also similar in both countries. On the other hand, differences existed in how nurses execute these domains of nursing practice. These are the roles of nurses, nurse aides and family members, and the interpersonal relationships, and problem presentation and problem-solving strategies. American family members rarely participated in the patient's bedside nursing care, while Korean family members actively participated. American nurse aide participated in direct patient care, while Korean nurse aides did not. Also Korean nurses were participated more in administering and managing the patient's diagnostic and treatment modalities, while American nurses focused on the needs and demands of the patient. In terms of interpersonal relationships, American patients were more self-centered and demanding than Korean. American nurses focused more on the right of individuals while Korean nurses were more oriented to harmony with the coworkers. With inferiors and superiors, American members were more egalitarian, while Koreans tended to be hierarchical. In ways of suggesting problems, American nurses tended to pick out the problems more frequently than Korean nurses did. As to ways to solve the problems, American nurses relied heavily on explicit verbal explanations, while Korean nurses relied more on bodily action and behaviors. The results of this comparative study contribute to nursing by adding knowledge on the theory of culture care by describing the similarities and differences in nursing practice between Korea and the United States.