Objective: Antibiotics are frequently prescribed in dentistry as a prophylaxis and/or for the management of infections in the oro-facial regions. It is known that indiscriminate usage of antibiotics often can lead to development of resistance and thus the topic is receiving a great deal of consideration in the literature. Most of the studies are conducted among dentist and was found that overuse and abuse of antibiotics are practiced. It is very important that dental students are cognizant and well-informed regarding antibiotics. The difficulties if identified during their undergraduate level can be used to improve their skill of prescription and thus avoid overuse of antibiotics in their future clinical set up. This research aim toassess the knowledge of dental undergraduates regarding the use of antibiotics in various clinical conditions, antibiotic prophylaxis and the problems encountered in writing the prescription. Method: Both male and female students of level 10, 11, and 12 students of King Khalid University –College of Dentistry were selected for the study. Questionnaire was used and the responses were analyzed. Results: Most common error faced during prescription was, not knowing the brand names and dosage. Only 40% students think that antibiotics have to be prescribed when there is evidence of systemic spread. 53.4% students consider antibiotics to prevent post-operative complications. 16.5% consider prescription when specific treatment has to be delayed and when there is patients’ expectation for a prescription. 18.3% consider antibiotic before any surgical procedure. 12.3% think that antibiotics have to be given in acute pulpitis and 28.5% believe that it has to be given in acute infection before drainage. 13.4% consider antibiotics in routine extractions. Satisfactory knowledge regarding the various situations where antibiotic prophylaxis is used was lacking. Majority think that there is need to conduct a workshop on rational use of antibiotics at University. Conclusion: Though majority have responded satisfactorily, there is a requirement for the development of prescribing guidelines and educational initiatives regarding sensible and right use of the antibiotics and has to be stressed to dental undergraduates within schools for refining the present scenario.