As individuals with Cystic Fibrosis (CF) live longer, they can develop complications such as Cystic Fibrosis Related Diabetes (CFRD), the most common complication seen in adults with CF. Those who develop CFRD experience accelerated decline in pulmonary function and higher rates of early mortality than those without CFRD, suggesting that CFRD is a sentinel event in that person's life. Recent evidence suggests that early recognition of CFRD and tight blood glucose control mitigates some negative impacts on health. Limited research describes risk factors that predict the development of CFRD. Proposed risk factors include use of a gastrostomy tube (g-tube) for enteral feeding, low body mass index (BMI) and lower pulmonary function. The goal of this study was to determine clinical characteristics that predict the development of impaired glucose tolerance (IGT) or CFRD among children and adolescents with CF. We anticipated that regular use of a g-tube for enteral feeding, decline in pulmonary function and decline in BMI z-scores would be associated with development of IGT and/or CFRD among children and adolescents with CF.