Caring is an elusive phenomenon but this should not prevent the development and validation of reliable quantitative tools for studying this concept in large samples of nurses. The present paper reports on the content analysis of a questionnaire called the Caring Dimensions Inventory (CDI). The CDI was content validated in terms of existing conceptualization of caring and research in this area and also in terms of a nursing taxonomy and its representation in popular United Kingdom nursing publications. The CDI was administered to a large sample of nurses working in Scotland and data were obtained from 1430 qualified and student nurses. The internal consistency of the CDI items related to perceptions of caring was established and the scalability of a sub-set of CDI items was demonstrated. The CDI scale was related to the constructs of age and sex of respondents. Possibilities for further analysis and development of the CDI are discussed.