Usability of a Web Based Library Systems (WBLS) is a major quality attribute. Checklists have become common and easy method to evaluate the usability of these WBLS; however the available checklists support evaluation of general usability aspects of WBLS only. The domain specific usability aspects are required to maximize the usability for such systems. This research proposes and validates a checklist based usability evaluation method that supports the evaluation of general as well as specific usability aspects of WBLS. The usability evaluation checklist is proposed based on analysis of literature and data of a controlled experiment. The checklist is validated in comparison to the “Academic Library Website Evaluation Checklist” via another controlled experiment. The proposed checklist is applied to the WBLS of universities in Pakistan. The manual and statistical result shows that, the proposed usability evaluation checklist identifies more general and specific usability aspects. It is found that both the checklists are equally efficient while identifying the usability errors. The proposed checklist is beneficial for the academia as well as industry to evaluate the usability of WBLS to an optimal level.