The impacts of coronavirus disease-2019 (COVID-19) on nasal mucociliary clearance (MCC) have shown conflicting results. The aim of this study was to determine whether COVID-19 infections affect nasal mucociliary activity using the saccharin test to measure nasal MCC time. This prospective comparative investigation included 25 patients with COVID-19 infection and 25 healthy controls. The nasal MCC time was assessed using the saccharin test. Saccharin test was applied to COVID-19 patients between the 10th and 20th days of COVID-19 test positivity. Patients admitted to the otolaryngology outpatient clinic with non-nasal symptoms and no history of COVID-19 infection served as the control subjects. Age, gender distribution, smoking, and alcohol usage, and the existence of other systemic disorders had no statistically significant differences between the groups (p = 0.25, p = 0.77, p = 1.00, p = 0.28, p = 0.54, respectively). The COVID-19 group had a mean nasal MCC time of 12.00 ± 2.51 min, compared to 9.77 ± 2.51 min in the control group. The nasal MCC time in the COVID-19 group was statistically significantly longer (p = 0.043). The COVID-19 infection negatively affects mucociliary activity and causes prolongation of MCC. As the nasal defense mechanism weakens in the early period after COVID-19 infection, susceptibility to respiratory infections may occur.