"Caring" has always been considered a natural and integral aspect of nursing. It is the core and essence of nursing. The human caring theory developed by Watson in the late 1970s (1975-1979) is a grand theory embracing ten carative factors. Swanson proposed her caring theory, a middle range theory that embraces five caring processes, in 1991. Although both Watson and Swanson have indicated that integration of their two theories may increase overall reliability, we must better understand their mutual similarities and differences in order to achieve an application suited to global circumstances. The purpose of this article was to compare and analyze the two caring theories. This article describes the basics of the two theories, discusses articles related to both in the literature and then describes current domestic and international applications. This article is intended to help health professionals better understand the underlying purpose of "caring" and to provide guidelines and points of reference for caring behaviors. It is hoped that such may also enhance caring behavior in practice and core nursing competencies as well as enrich the humanistic aspect of nursing, a profession that increasingly regimented by standard procedures and the requirements of technology.