This study aims at contributing to the advancement of the field of Library and Information Science, academia, and the wider society by exploring the scientific research production on the topic of digital library sustainability as this is represented in two bibliometric databases: Web of Science and Scopus. It also attempts to make a methodological point about how scientific domains should be investigated using bibliometrics. Lastly, it investigates the extent to which the Sustainable Development Goals (SDGs), set out by the United Nations in 2015, constitute a study object in the existing literature within the particular field of study. To achieve these aims, a bibliometric analysis of academic literature (i.e., articles, review articles, books, book chapters, and conference papers) published between 1997 and 2023 was conducted. Moreover, existing research in relation to the SDGs was analyzed using the relevant filtering options available at each of the two databases. As a means for triangulation, the data sets exported from the two databases were examined separately and their results compared. The results showed an upward trend in scientific production on the topic. Nevertheless, the discussion around it is still at preliminary stages as proven by the limited number of (a) publications on the topic, (b) authors systematically researching it, and (c) inter-author and inter-country collaborations. The study also revealed significant differences in the way SDGs are mapped in each of the two databases allowing for questioning whether SDG database mappings may be trusted, and highlighting the need for more research on the issue.