Abstract. Objectives: The study's aim was to assess the medical students' knowledge and understanding of concepts related to basic nanotechnology and its applications in nanomedicine among medical students at King Saud University. Methods: An observational cross-sectional study was carried out by using an online questionnaire that was sent to all the medical students studying at King Saud University during the summer of 2016 July-August. The sample size of the study was 162 medical students. The questionnaire consisted of 11 items, including both fi xed and free answer-type questions. The questionnaire was sent to 1413 medical students, with a response percentage of 8.72%. Results: Students' perception of the basic nanotechnology was assessed, 63.0% (n = 102) of the students identifi ed the correct defi nition of nanoparticle size. Unfortunately, only 40.7% (n = 66) of the students heard about nanomedicine. Most of the information sources where from university 25.3%, 24.1% from internet, and 11% from television. 81.8% of our medical students, had little knowledge about the risk-benefi ts of nanomedicine. Interestingly, about 72.8% (n = 118) of the students think that nanotechnology is not effectively used in the medical fi eld. Conclusion: Medical students at king Saud university, showed that they have inadequate knowledge about nanotechnology and its applications in nanomedicine. Nanomedicine education should be implemented in the curriculum of the medical colleges in Saudi Arabia, to improve the awareness and future involvement in nanomedicine.