This study investigates the challenges associated with postgraduate students’ awareness and use of online journals in Nigerian universities. The study adopted the descriptive survey design. The population of the study comprised 10, 775 registered postgraduate students in federal and state universities in south-south zone of Nigeria. Based on the Krejcie and Morgan sample size determination table, a sample size of 370 postgraduate students were chosen for the study. The questionnaire was the instrument used for data collection. Copies of the questionnaire were distributed by hand by the researchers with the help of research assistants. Mean and standard deviation were used to analyse the data from the questionnaire. The major findings challenges associated with postgraduate students’ awareness and use of online journals were identified to include absence of enlightenment on online journals by lecturers (𝑋̅2.94,SD=.87), lack of knowledge of publishers of online journals (𝑋̅2.67,SD=.98), lack of user education on online journals from university libraries (𝑋̅2.80,SD=.93), inadequate computer systems in university libraries (𝑋̅3.58,SD=.73), frequent power outages in libraries (𝑋̅3.48,SD=.66), and slow internet connectivity in university libraries (𝑋̅2.96,SD=.94) among others. Respondents in the study proffered several strategies for enhancing awareness and use of online journals. Based on the findings, it was recommended that the cost of data bundle should be reduced by Internet service providers, particularly for postgraduate students to enhance the use of online journals. University libraries should engage in aggressive awareness campaign on online journals and their usefulness for effective research in universities. Additionally, university libraries should create a database of open access online journals to enable users search full text articles online from various publishers.
 Keywords: Online Journals, Awareness, Use, Universities, Challenges