After having been subjected to radical mastectomy for breast cancer, women are usually fitted with an external breast prosthesis. Different types of prostheses are available, but oncology nurses have few data enabling them to advise their patients adequately. In this prospective randomized crossover study of 101 women undergoing one-sided mastectomy for breast cancer, the self-adhesive breast prosthesis was compared with the traditional external prosthesis. Questionnaires were used to evaluate the woman's judgment of the prosthesis in relation to her final preference for one type of prosthesis. Complete data were available for 91 women, 59.3% of whom finally preferred the self-adhesive type. Preference was independent of age, randomization, order, or the possible use of adjuvant chemotherapy. Satisfaction with the self-adhesive prosthesis was independent of randomization order but satisfaction with the traditional type was significantly more when it was the first type of prosthesis. Preference for the self-adhesive prosthesis over the traditional type mas mainly related to an increased perception of the prosthesis as a part of the body. Preference for the traditional prosthesis over the other type was mainly related to the greater ease of application and the lesser local irritation of the skin. Findings from this study can be useful in oncology nursing practice.