The aim of this investigation was to delineate the concepts contributing to the Exercise of Self-Care Agency (ESCA) scale developed by Kearney and Fleischer (1979) and to test its construct and discriminant validity. Using factor analytic techniques upon data generated by 506 subjects, the concepts of Self-Concept, Initiative and Responsibility, Knowledge and Information Seeking, and Passivity emerged. These findings are congruent with the theoretical work of the Nursing Conference Development Group (1973) and Kearney and Fleischer. The factors were found to discriminate these concepts among 3 different samples. Recommendations are made for revision, further research, and use of the instrument in practice.