Introduction: The coronavirus disease (COVID-19) is caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2). The disease is spread by droplet transmission from person to person. After recovering from the acute form of the disease, people may develop post-COVID-19 syndrome. Post-COVID-19 syndrome is characterized by specific symptoms that can last for a long time. The aim of the research: to determine the effect of respiratory physiotherapy in patients with post-COVID-19 syndrome. The values of the 6-minute walk test, left and right hand grip strength and MIP (maximum inspiratory pressure) before and after respiratory physiotherapy were compared. Subjects and methods: 40 subjects diagnosed with post-COVID-19 syndrome participated in this study. The symptoms that affected the patients were: a feeling of loss of breath, a decrease in fitness and shortness of breath. The research is retrospective. The data of MIP, 6-minute walking test and left and right hand strength test were taken before and after respiratory physiotherapy. Results: a statistically significant difference was found in the 6-minute walking test expressed in meters before and after respiratory physiotherapy (p=0.014). A statistically significant difference was found by measuring the grip strength of the left hand (p=0.000) and the right hand (p=0.000) before and after respiratory physiotherapy. By measuring MIP (maximum inspiratory pressure), a statistically significant difference (p=0.000) was also found before and after respiratory physiotherapy. Values show improvement after respiratory physiotherapy. Conclusion: the results show the success of respiratory physiotherapy in patients suffering from post-COVID-19 syndrome.