The purpose of this study was to define critical thinking in nursing. A Delphi technique with 5 rounds of input was used to achieve this purpose. An international panel of expert nurses from nine countries: Brazil, Canada, England, Iceland, Japan, Korea, Netherlands, Thailand, and 23 states in the U.S. participated in this study between 1995 and 1998. A consensus definition (statement) of critical thinking in nursing was achieved. The panel also identified and defined 10 habits of the mind (affective components) and 7 skills (cognitive components) of critical thinking in nursing. The habits of the mind of critical thinking in nursing included: confidence, contextual perspective, creativity, flexibility, inquisitiveness, intellectual integrity, intuition, open-mindedness, perseverance, and reflection. Skills of critical thinking in nursing included: analyzing, applying standards, discriminating, information seeking, logical reasoning, predicting and transforming knowledge. These findings can be used by practitioners, educators and researchers to advance understanding of the essential role of critical thinking in nursing.