This review attempts to summarize the important areas of cystic fibrosis (CF) clinical research. Some of the trials outlined are incomplete or the data are not yet published. Focus is given to gene therapy and to studies that probe our understanding of CF cellular biology by attempting to correct or bypass abnormal cystic fibrosis transmembrane regulator. Trials of more immediate clinical value include improvement of mucociliary transport and inhaled tobramycin. Finally, mention is made of the significant nonpulmonary treatments for CF including ursodeoxycholic acid for CF liver disease and intracytoplasmic sperm injection for male infertility.