March 11, 2020 WHO has declared the COVID-19 coronavirus pandemic. The European Society for Cystic Fibrosis (ECFS) has developed the ECFSCOVID- 19 surveillance program to collect information on the characteristics of COVID-19 in patients with cystic fibrosis (CF). CF centers in the Russian Federation also joined the ECFS study. The ECFS collected information only through national Registers. In our country, the national register of CF patients has existed since 2011, its data is included in the European Register. Тo analyze the prevalence and course of COVID-19 in adult CF patients in Saint-Petersburg and the Leningrad region.Methods. From 11.03.20 to 24.12.20, 10 cases of adult CF patients (4 women, 6 men) with COVID-19 were analyzed in Saint-Petersburg and the Leningrad region. At the beginning of the study, 56 adult CF patients lived in Saint-Petersburg and Leningrad Region. All patients were monitored remotely by telephone, in case of ARVI symptoms, disease exacerbation, a PCR smear was performed on SARS-CoV-2, therapy was prescribed remotely, and inpatient treatment was prescribed if indicated.Results. COVID-19 was diagnosed in 10 adult CF patients aged 21 to 43 years. Two patients (32-year-old male and 31-year-old female with severe mixed cystic fibrosis form) were hospitalized with polysegmental pneumonia. 8 people were treated on an outpatient basis. Only 1 outpatient patient aged 43 years had pronounced clinical manifestations of COVID-19, the condition was regarded as moderate, the remaining outpatient patients suffered from a mild ARI disease. All patients were treated with positive dynamics. During the period of this follow – up, 3 CF patients (2 men, 1 woman) died, the death cause was the respiratory failure progression. Clinical and radiological, repeated laboratory data for COVID-19 were not obtained. At the point of December 24, 2020 53 adult CF patients are alive.Conclusion. According to our data, the incidence of COVID-19 among adult CF patients in Saint-Petersburg and the Leningrad Region was 17.85%, which is a lower indicator than in the general population. The disease was rarely severe, and effective treatment was noted in outpatient settings. There were no deaths from COVID-19.