Introduction: Medical knowledge is rapidly expanding and updating. It is very important that students can timely access to information and the latest scientific evidence without any time and place limitation. The smartphone is one of ICT tools that adopted greatly by healthcare professionals. Today, the most medical sciences universities have provided smartphone as an educational aid tool and acquisition licenses for medical apps resources in training of their students. Aim: This research was conducted to determine common smartphone applications among medical students of Urmia University of medical sciences and to identify barriers in using them. Materials and Methods: This research was a descriptive type of study carried out in 2016. Population of the study included 530 medical students completing the clinical course in Urmia University of Medical Sciences. Data were collected using researcher-developed questionnaire. The validity of it determined based on the view of experts and the reliability of it obtained by calculating the value of CronbachÂ’s alpha (α = 0.82). Results: 82.3% of the students had smartphone, which in terms of operating system the highest was related Andriod (53%) and iPhone (32%). The most common applications used often by medical students included Up to date, PubSearch, Calculate by QxMD, Epocrates and OMnio. Lack of accreditation of medical apps by valid health institutions (4.63), lack of support and update of applications by their developers (4.44), lack of adequate skill to use applications (4.25) are the most important barriers in using these applications among students. Conclusion: To assurance quality of medical apps, it seems very important that academic and healthcare organizations should be involved to develop and update the apps and also provided guidelines for accreditation of apps. It is recommended that for promotion of knowledge and skill of students provide essential educations.