This study, aimed to evaluate the difference in mucociliary clearance among volunteers who underwent Ramadan versus Nineveh fasting regimens as well as the difference between the fasting period and 4 weeks following the fasting period in both groups. In this study, two different fasting groups were established: Ramadan (fasting for an average of 15 h for 29 consecutive days, n = 40) and Nineveh (60 h of nonstop fasting, n = 26). Subjects in each group underwent saccharin testing twice: at the end of the fasting period prior to resumption of eating and at 4 weeks after the end of Ramadan or Nineveh fasting. Statistical analysis was performed using the Mann-Whitney U-test, Wilcoxon, Chi-square, and paired t test. A p value less than 0.05 was considered statistically significant. Forty subjects who underwent Ramadan fasting and 26 subjects who underwent Nineveh fasting were included in this study. Of the 66 study participants, 34 (51.5 %) were men and 32 (48.5 %) were women. Their median age was 31 years (range 17-70 years) for Nineveh fasting subjects and 40 years (range 17-70 years) for Ramadan fasting subjects. Chi-square tests revealed no significant difference between the Ramadan and Nineveh fasting groups in gender (p = 0.418), and the Mann-Whitney U-test showed no difference in age. A statistically significant difference was found in the mucociliary clearance time between the Nineveh fasting and non-fasting periods (p = 0.013). Using Wilcoxon signed-rank tests, we found no significant difference in the mucociliary clearance time between the Ramadan fasting and control (4 weeks after the fasting period) periods (p = 0.121). The percentage difference between the fasting and control periods was similar between groups and was not statistically significant for the Ramadan and Nineveh fasting groups (p = 0.086). The results of the present study indicated that long-term fasting with hypohydration contributed to the deterioration of nasal mucociliary clearance. Our data indicate that optimal hydration, sleep patterns, and fasting times contribute to proper mucociliary clearance.