Background: Asthma still the mainly prevalence chronic respiratory disease affecting individuals in different ages. The objective of this study was to find out the prevalence of asthma, and its triggering factors among medical students in the College of Medicine University of Hai'l city, Saudi Arabia. Methodology: The study investigated 198 students using online questionnaire. Results: The 198 male medical studentsaged between 20 -27 years with mean age of 21.5. The overall prevalence of asthma in in the medical students at the College of Medicine University of Hai'l was 10%.Regarding to things that aggravates asthma symptomsdust 5/20(25%), smoke 2/20(10%), dust+smoke 4/20(20%), dust+stress 1/20(5%), dust+smoke+stress+animals 2/20(10%), dust+smoke+cold weather 3/2(15%), dust+animal+stress 1/20(5%) and dust+coldweather+animals 2/20(10%). Conclusion: The prevalence of asthma in medical students is relatively high compared to global prevalence rates. The most common allergies triggering asthma symptoms in the college of Medicine, university of Hail, are dust, smoking, Animals and stress.