Once considered a childhood disease, cystic fibrosis is now also a disease of adults. Increased longevity has resulted in the aging of the cystic fibrosis population. The consequent age-related medical problems among adults with cystic fibrosis have increased medical care needs. These needs are being met by a growing number of non-pediatric pulmonologists and other non-pediatric specialists. The objective of this review was to summarize the current knowledge about diagnosis and treatment in adult cystic fibrosis. In most cases, the diagnosis is suggested by manifestations of chronic sinopulmonary disease and exocrine pancreatic insufficiency. The diagnosis is confirmed by a positive sweat test result. Adult patients may, however, present pancreatic sufficiency and atypical clinical features, sometimes in combination with normal or borderline sweat test results. In such cases, identifying cystic fibrosis mutations and measuring nasal potential difference can have diagnostic utility. The standard therapeutic approach to pulmonary disease includes the use of antibiotics, airway clearance, exercise, mucolytics, bronchodilators, oxygen therapy, anti-inflammatory agents and nutritional support. Appropriate application of these therapies results in most cystic fibrosis patients surviving into adulthood with an acceptable quality of life.