Objective: The purpose of this research is to evaluate the hospital libraries service quality of Shahid Beheshti University of Medical Sciences from the users’ perspectives based on the LibQUAL+ model. Furthermore, is to make a comparison between library services of general hospitals versus specialized one. Materials and methods: The survey used the LibQUAL+ model to evaluate service quality of libraries of general as well as specialized hospitals of Shahid Beheshti University of Medical Sciences (12 libraries) (Iran). The data were collected from library clients by administering the LibQUAL+ questionnaire in a printed format. Results: It has been revealed that hospital libraries have succeeded in satisfying the minimum expectations of its users but could not meet the customers’ desired expectations that make them delighted. Information Control is the least satisfying dimension, whereas the Library as a place is the most satisfying dimension. The users are more satisfied with general hospitals library services rather than specialized ones in all dimensions. Conclusion: The hospital libraries failed to meet the minimum expectations of users in two dimensions of information control and the library as a place. It is suggested to improve the quality and quantity of library facilities and to create a pleasant atmosphere for users by considering a proper space for the study of clients. This will lead to help hospital libraries to meet the desired level of requirements of users.