It is important to find indicators of quality nursing care to establish the excellence of nursing practice and for the development of nursing as a profession. Caring is one of the indicators which can represent professional nursing care. The purpose of this study was to develop a measurement tool of caring that could be used as an instrument for the evaluation of quality of nursing care. The Target population for the developed tool of caring is the adult patient. The mearsurement tool of caring was developed through the following steps. (1) A list of caring behaviors was made using qualitative researches on caring that has been done in Korea. (2) Caring behaviors in nurses were selected using the list of caring behaviors developed from Watson's 10 factors of caring, (3) Items for the measurement tool of caring were developed using the caring behaviors of nurses (4) Content validity of the developed items was evaluated by an expert panel. (5) The mearsurement tool of caring was developed after a pilot study (6) Internal consistency, and construct validity of the developed tool were verified. (7) The mearsurement tool of caring with the items verified for the internal consistency and construct validity was confirmed. As a result of the study, a mearsurement tool of caring, composed of 27 items with 3 factors, was developed. The Reliability coefficient of the tool was . 9578. The tool is a 5 point Likert scale. The factors of the tool and the number of items for each factor are, 1) accessibility and availablility, 15 items; 2) emotional support and giving information, 8 items; 3) providing a protective environment, 4 items.