This paper presents an empirical investigation on user’s satisfaction based on the expectation disconfirmation paradigm theory. The study selects a sample of 332 people from 2449 graduate students who were enrolled at the Birjand University. The study uses a questionnaire developed by Isac and Rusu (2014) [Isac, F. L., & Rusu, S. (2014). Theories of user’s satisfaction and the operationalization of the expectation disconfirmation paradigm. Economic series, university of Targu, 2 (1), 82-88.]. Using path analysis, the study has determined that perceived usefulness and personal experience had the highest impact on users’ satisfaction in electronic library usage. In addition, there was a negative relationship between user interface and users’ satisfaction.