Introduction: Librarians are faced with a large volume of information and electronic resources, which causes stress. The purpose of this research was to determine job stressors among librarians of University of Medical Sciences, Tehran city, Iran in 2014.

Methods: This study was survey research. 185 librarians were studied in this research which data was collected by questionnaire. Questionnaire validity confirmed by specialists and a number of experts in the fields of psychology, mental health and science information. Its reliability determined by Cronbach’s alpha, as (r = 0.824). Data analyzed using SPSS 21 software and descriptive statistics and inferential tests.

Results: New technology increases the incentive to work, save time, increase the responsibility. In relation to the rating of occupational stressors, respectively, the greatest impact include lack of understanding of the nature of the job, their familiarity with the English language, And minimal impact on the question of inconsistency in average professional expertise with organizational work as well as different training courses with job requirements In general, electronic resources in libraries has caused stress. The mean and standard deviation 2.66±1.210.

Conclusion: The results showed the Librarians introduced stressors are, Failure to inform the authorities of the nature of the work, ambiguity in the role of staff, lack of ability, need to support and unfamiliarity with the English language in with the advent of electronic resources and environmental changes.