Introduction: Patients with Cystic Fibrosis (CF) have increasing rates of hospitalization. We analyzed the burden and predictors of thirty-day readmission among patients with CF in the U.S. Material and methods: Nationwide Readmission Database (NRD) 2013 was used to identify adults with CF who were hospitalized. These individuals were followed to determine the prevalence of readmission within thirty days of index discharge. Cox proportional hazard regression was used to identify independent predictors of readmission. Results: There were 14,616 index admissions of adults with CF in 2013. Of these, 2,606 (17.8%) patients were readmitted within 30 days of discharge. Female sex and chronic anemia were independent predictors of readmission. The most common causes of readmission were pulmonary exacerbation (31%), lung transplant complications (5.2%), and septicemia (3.4%). Conclusion: Readmissions are frequent among adults with CF and contribute to significant healthcare burden and cost among this population.