Adult cystic fibrosis patients from the Rush University Medical Center Adult Cystic Fibrosis Program will be recruited for a prospective before and after cohort study to evaluate patient preference for either the TOBI Podhaler or inhaled tobramycin solution and compare the efficacy of the TOBI Podhaler to tobramycin inhaled solution. This project will evaluate the potential differences in efficacy, medication adherence, treatment time, side effects/adverse effects, quality of life, and identify patient preferences between the use of TIP and TIS. Measurements after a 28-day cycle of tobramycin inhaled solution, first 28-day cycle of TOBI Podhaler and third 28-day cycle of TOBI Podhaler will include FEV1, number of acute pulmonary exacerbations, adherence, cough frequency, sputum characteristics, and side effects or adverse events. The quality of life as assessed by the Cystic Fibrosis Questionnaire-Revised (CFQ-R) will be measured after a 28-day cycle of tobramycin inhaled solution and the third 28-day cycle of TOBI Podhaler. The FEV1 values, number of missed treatments, and total treatment time will be analyzed through a repeated measures analysis of variance. Comparisons of the CFQ-R data before and after the switch to the TPI will be made with the Student's t-test.