The purpose of this study was to explore the lived experience of patients undergoing an excisional breast biopsy. It has been determined that women who feel a lump or a lesion in their breast delay seeking medical treatment because it could be cancer and they might need a mastectomy and/or the cancer may not be treatable. After women go to a health-care facility and are told that they need to have a biopsy to make a clear diagnosis they want to have the biopsy performed as soon as possible. A phenomenological approach from a Heideggerian hermeneutical perspective was used. Participants were 20 patients who had an excisional breast biopsy in the day surgery of a university research and training hospital general surgery division under general anaesthesia between the dates of 1 December 2004-30 June 2005 and who returned one week later for monitoring, who were over 18 years old and who volunteered to participate in the research. Data were collected using in-depth interviewing and analysed using the principles of Heideggerian hermeneutics. Three themes were identified: need for information, fear, spiritual needs. It was determined that patients undergoing excisional breast biopsy had significant information and spiritual needs and experienced a fear of having cancer, losing their breasts and dying in surgery. Relevance to clinical practice. Although there are many studies about breast cancer and day surgery patients' experiences in the literature, no studies were found about patients' experiences with day surgery excisional breast biopsy procedures. The results provide a possible framework for patient care.