The Carlos P. Romulo Library caters to the DFA and FSI, other government and non-government institutions, and the academe. It provides reference services for inquiries and literature searching as well as information services through its Library Update and Special Subject Bibliographies.

The Library houses a collection of approximately 9,418 volumes of books and 50 titles of newspapers, journals, and magazines, both domestic and foreign, and 67 titles of non-print materials. It also serves as a repository of annual/post reports of Philippine foreign service establishments and the originals of treaties and agreements entered into by the Philippine government. At present the Library also houses the ASEAN, UNIO and UNESCO collection.

The FSI Library, which was established in 1977, was renamed Carlos P. Romulo Library in 1995 in honor of Carlos P. Romulo, the secretary of foreign affairs who served the longest term.