Approximately half of all cancer patients receive radiation therapy sometime during the course of illness. In combination with early diagnosis, radiotherapy offers a good probability of increased survival rate. Because external radiation therapy is usually provided on an outpatient basis, individuals receiving this mode of treatment are responsible for their own self-care.The purpose of this study was to identify therapeutic self-care demands as expressed by outpatients receiving radiation therapy. Radiation therapy, physiology, Orem's concept of self-care, and Magoon's constructivist methodology were synthesized as a foundation for the study. A descriptive survey research design was used. An open-ended interview technique, constructed and conducted by the researcher, was utilized to collect the data. Thirty participants were asked to verbally express changes, if any, which occurred in his or her life since the radiation treatments began. The data were collected by the use of a tape recorder, transcribed, and categorized according to the six universal self-care requisites identified by Orem. In order to establish reliability, peers of the researcher who were familiar with the self-care theory categorized the data also.