Objectives: Medical students and practitioners need to evaluate medical information found on the Internet. Most current medical students are familiar with the Internet, but their ability to evaluate material may require additional skills. We aimed to discover the extent to which medical students can evaluate medical websites, criteria used, factors affecting their abilities, and whether a teaching intervention could rectify problems. Methods: A class of 181 undergraduate medical students evaluated an unreliable medically-related website, received a teaching intervention on web site evaluation criteria, and re-evaluated the same site. Results: A total of 149 (82.3%) students participated. Students spent a mean of 4.69 hours per day on the Internet; there were no significant correlations between demographic indicators and Internet time. On Likert Scales of 1-10, students’ scores ranged from 5-6, with no significant differences between the pre- and post- evaluations, except increased polarisation away from the mean. Qualitative comments indicated an awareness of relevant criteria, but an overall inability to critically apply them. Conclusion: The results indicate that one cannot make a blanket statement about medical students’ ability to evaluate medical websites, in spite of technological familiarity. The indications are that website evaluation should be viewed primarily from the information perspective, and that critical thinking ability may play a major role. Because of these overriding factors, short interventions are unlikely to have an impact, and other educational strategies should be developed. These are necessary to ensure that medical students can function independently as life-long learners and medical professionals. Keywords: Internet; Students, Medical; Oman.