Gene delivery in cystic fibrosis is hampered by extracellular and intracellular biological barriers and inefficient vectors. Although progress is evident, continued bioengineering of DNA, vectors, and delivery technologies will be critical to ensure biocompatibility, safety, and therapeutic effectiveness. Both viral and nonviral vectors demonstrate insufficient gene expression to adequately correct chloride ion and respiratory homeostasis, but vector modifications and novel vector types continue to advance understanding of transfection processes, immunobiological responses, and cystic fibrosis pathology. Interactions of toll-like receptors and other coreceptors may be critical components of cystic fibrosis immunobiology but additional research will be needed before causative associations are widely established; however, receptor modulation provides a theoretical framework to develop new therapeutic approaches. Clinical-phase pharmacotherapies offer short-term promise to restore electrolyte imbalance and/or symptomatology, but it may be many years before gene therapy offers a curative solution for the disease.