The open science initiatives, growing number of open resources (digital collections, institutional repositories, open educational resources, scientific data, etc.), changing user information needs and preferences hang like a sword of Damocles over the libraries and threaten with the absence of demand for science and education support. The purpose of the study is to identify librarians’ awareness of the world open access resources (OAR) and their role in developing library and information products and services. The author analyzes OAR structure, Russian librarians’ awareness of 50 largest OAR structured by document type (books and articles, dissertation, preprints, data sets, learning materials, patents and standards, encyclopedias and dictionaries, scientific information retrieval systems). She also emphasizes the problems of mastering global OAR by Russian academic librarians, their interest toward practical use of OAR in library and information user services. The findings of the study demonstrate the possibility for the libraries to build their value in the market of information OAR and to become essential part of the modern science information ecosystem, to assist in managing scientific content and document retrieval, and to provide subject-oriented teaching and consulting of users.