Fasting is a fundamental practice in many religions worldwide. The holy month of Ramadan is a sacred duty that can diversely affect different diseases. Refraining from some medications during Ramadan can adversely affect patients with asthma. This research evaluates the role of fasting on disease severity and spirometry parameters in patients with asthma before, during, and after Ramadan. This research enrolled 120 patients with asthma who were referred to the clinic during Ramadan and allocated them to fasting and non fasting groups. All the patients underwent Spirometry before and at the end of Ramadan. The rate of control over asthma pre- and post Ramadan was assessed, followed by comparing the findings in each group and between the two groups. There was no significant difference in the spirometric parameters pre- and post-Ramadan between fasting and non-fasting groups and in each group. The difference in asthma control pre- and post-Ramadan was insignificant between the two groups. Nevertheless, FEV1 change in the fasting group was significantly higher than in the non-fasting group. Fasting during Ramadan exerts no significant effect on the severity of asthma and spirometric parameters in patients with moderate to severe asthma. Thus, regular inhalation therapy during Ramadan with altering the hours of medication consumption can efficiently avert exacerbation or asthma attacks.