This paper evaluates the extent of use of electronic resources by postgraduate library users in University libraries in South East Nigeria. The study ascertains the types of electronic resources available in the libraries under study and finds out the extent of use of these electronic resources among postgraduate library users in the University Libraries understudy. It employed a descriptive survey design. The population of the study was 2595 respondents consisting of 2509 postgraduate users and 86 librarians in Collection Development, Serials and Digital library (e-library). A 10% proportionate sampling technique was used to select a sample of 251 user respondents while all the 86 librarians working in collection development, serials, and digital library units (e-library) were used. The survey used questionnaire and interview as instruments for data collection. Data collected were tabulated and analyzed using simple statistics (mean). An aggregate of twenty (20) electronic resources were identified in the university libraries under study. The resources that are available in all the libraries under study are online databases such as EBSCO-Host, Medline, OARE, AGORA, AJOL, Jstor Nexus, e-books, and e-journals especially free online resources. Also, the assessment of the extent of use of electronic resources by the postgraduate student’s users revealed that majority of the electronic resources is used to a great extent.