: Advances in the publishing world have emerged new models of digital library development. Open access schemes are expanding their presence and realize the idea of digital library in various means. While user-centered evaluation of digital libraries has drawn considerable attention during the last years, these systems are currently view from the publishing, economic and scientometric perspectives. The present study explores the concepts of usefulness and usability in the evaluation of an e-print archive. The results demonstrate that several attributes of usefulness and usability, as well as functionalities commonly met in these systems, affect user interaction and satisfaction.