To provide practice recommendations for genetic counselors whose clients are considering cystic fibrosis (CF) carrier testing or seeking information regarding CF molecular test results. The goals of these recommendations are to: 1) Provide updated information about the natural history, diagnosis, and treatment of CF and related conditions. 2) Supplement genetic counselors' knowledge and understanding of the available carrier screening and diagnostic testing options. 3) Describe the current state of genotype/phenotype correlations for CFTR mutations and an approach to interpreting both novel and previously described variants. 4) Provide a framework for genetic counselors to assist clients' decision-making regarding CF carrier testing, prenatal diagnosis, and pregnancy management. Disclaimer The practice guidelines of the National Society of Genetic Counselors (NSGC) are developed by members of the NSGC to assist genetic counselors and other health care providers in making decisions about appropriate management of genetic concerns; including access to and/or delivery of services. Each practice guideline focuses on a clinical or practice-based issue, and is the result of a review and analysis of current professional literature believed to be reliable. As such, information and recommendations within the NSGC practice guidelines reflect the current scientific and clinical knowledge at the time of publication, are only current as of their publication date, and are subject to change without notice as advances emerge.In addition, variations in practice, which take into account the needs of the individual patient and the resources and limitations unique to the institution or type of practice, may warrant approaches, treatments and/or procedures that differ from the recommendations outlined in this guideline. Therefore, these recommendations should not be construed as dictating an exclusive course of management, nor does the use of such recommendations guarantee a particular outcome. Genetic counseling practice guidelines are never intended to displace a health care provider's best medical judgment based on the clinical circumstances of a particular patient or patient population.Practice guidelines are published by NSGC for educational and informational purposes only, and NSGC does not "approve" or "endorse" any specific methods, practices, or sources of information.