To evaluate and compare the knowledge and attitude about Basic Life Support (BLS) and medical emergencies among undergraduate dental students and interns at the College of Dentistry, Taibah University, Al Madinah , Saudi Arabia. A previously validated, self-administered, anonymous, closed structured online questionnaire was distributed by email to the clinical year's students and interns. The questionnaires consisted of demographic data, knowledge and attitude of the participants toward BLS and Medical emergencies. 112 questionnaires were filled, with a response rate of (55.4%). Most of participants knew the abbreviation of BLS and half of them answered the questions of knowledge correctly. Most of participants thought that all dental students and staff need to know more about BLS. The knowledge of undergraduate students and interns about BLS is inadequate and need to be improved but they have a positive attitude toward it.