of a dissertation at the University of Miami. Dissertation supervised by Professor Alexandra L. Quittner No. of pages in text. (70) Objective: CF is a progressive, life-shortening disease treated primarily with palliative medications. Among the consequences of the disease’s progression and daily treatments are discomfort and pain. Previous studies have suggested that pain is common in patients with CF; however, little is known about the factors associated with this pain or its impact on clinical outcomes. The relationships between pain and health outcomes over time, such as adherence and health-related quality of life (HRQOL), are largely unknown in this population. The purpose of this study was to systematically assess pain in adolescents with CF and evaluate its associations with adherence, social support, and HRQOL over a six-month period. Methods: The current study is part of a multi-center NIH SBIR Phase II randomized, controlled trial. The sample consisted of 95 participants, with a mean age of 15.69. Participants completed a battery of measures during three consecutive clinic visits, approximately 3 months apart. Participants also completed an online pain diary for the 6 days following each clinic visit. Diaries assessed pain intensity, location, duration, affective rating, and coping responses. Results: Overall, 73% of participants completed one or more of the online pain diaries across these time points, with 44% of the sample completing all six diaries. Pain was reported by 74.5% of participants. Of those who experienced pain, intensity was generally mild. Daily pain ratings, as assessed by online diaries, were highly variable within participants. Path analyses indicated that worse treatment adherence and poor social functioning were directly related higher pain and ultimately related to worse HRQOL. Conclusions: These results indicated that pain is common in adolescents with CF and that it interferes significantly with HRQOL. Treatment adherence appears to be particularly predictive of pain in this population. Regular assessment of pain and HRQOL is recommended.