Cystic fibrosis is a dysfunction in the exocrine glands as a result of mutation in the chloride channel called Cystic Fibrosis Transmembrane Regulator in the epithelial cell membrane. Structural and functional disorder in Cystic Fibrosis Transmembrane Regulator; it causes disruption of chloride transport in epithelial cell membranes of organs such as respiratory tract, pancreas, bile ducts, reproductive organs and gastrointestinal tract. Lung infection seen in patients with cystic fibrosis increases the prevalence of morbidity and mortality. Cystic fibrosis; The thickened secretions formed in the airways create a negative environment for the increase and persistence of infection. Because viral infections play an important role in the course of cystic fibrosis, patients with cystic fibrosis are thought to be at high risk of developing severe symptoms in the case of severe acute respiratory syndrome coronavirus-2 infection. However, among patients with cystic fibrosis, the incidence of acute respiratory syndrome coronavirus-2 (0.07%) was found to be below the average incidence (0.15%) in general populations, thanks to behaviors such as wearing a protective mask, little contact with people, or avoiding host factors. Patients with cystic fibrosis and their families face many challenges in managing the disease compared to the general population. It is very important to positively affect the health of individuals by applying personalized nutrition therapy in the treatment process of cystic fibrosis, which is managed by methods such as drug therapy, physiotherapy, exercise and medical nutrition therapy, especially during the pandemic period. Pandemic period; Difficulty in accessing food, social isolation and food insecurity may have caused changes in the nutritional habits of patients with cystic fibrosis. The aim of this review article is to examine the effect of COVID-19 in patients with cystic fibrosis and to evaluate medical nutrition therapy during the pandemic period.