This phenomenological study explored the pre-diagnosis experiences of 36 men and women who learned during their adult years that they had cystic fibrosis (CF), a disease usually diagnosed in children. Four mutually-exclusive pathways to diagnosis emerged during data analysis, each determined by the extent to which participants experienced symptoms growing up and the extent to which they suspected they had a serious disease. Themes describing the pathways were developed. Pre-diagnosis experiences were found to impact post-diagnosis experiences, as well as individuals' readiness for education, treatment, and support. Recommendations for CF caregivers, consistent with the expressed wishes of participants, also emerged. Findings revealed that, at least for CF, not all arrive at diagnosis having had similar experiences, suggesting individualized approaches to initiating treatment, education, and support. Although the literature largely conceptualizes chronic illness experience as beginning with diagnosis, this study highlights the pre-diagnosis period as an important focus for additional study.