This phenomenological study was designed to explore the lived experience of having cancer, as perceived by people who have been diagnosed and treated for cancer. The aim of the study was to add to the knowledge and understanding of this complex human phenomenon. Data were collected through in-depth interviews with nine people who were in the remission or recovery phase of cancer. The interviews were tape-recorded and transcribed verbatim for each participant. Through intersubjective interactions and thematic analysis, the essential description of the lived experience of having cancer was constructed. The overriding theme of the lived experience of having cancer is "experiencing existential changes." Five basic subthemes were identified in the participants accounts, all of which are part of the existential changes involved in the lived experience of having cancer. These are: uncertainty, vulnerability, isolation, discomfort, and redefinition. The study can increase the understanding of what it is like to have cancer.