The Library has over 100,000 books. Though the majority of books are in English, there are books in Sanskrit and other ancient and modern Indian languages and in European languages like Greek, Latin, Italian, German and French. Books are in the traditional areas of Indology and Oriental scholarship, but also include Biography, Genealogy, Politics, Economics, Science, Management, Travel and Fiction. 15,000 have been classified as rare and valuable books, and they include first editions of antiquarian books in Indian and European languages 

The total number of books and bound volumes of periodicals as on March 31, 2001 is 2,42,645. 

The Society is continuously augmenting its collections by purchasing new books with an allocated annual budget. Additionally, there is in place a Gift and Exchange scheme under which valuable collections are being donated by individuals over the decades, and the Society's publications and issues of its journal are being exchanged with those of other institutions. 

Historically too, the Society has been the recipient of valuable collections from several sources. The Government of Bombay took keen interest in the Society from its inception and presented numerous manuscripts given to the Court of Directors of the East India Company by orientalists like Dr.Taylor and Col. Miles. Since then, many important additions have been made through the generosity of leading administrators, educationists, philanthropists and scholars of the city including Mountstuart Elphinstone, A.M.T.Jackson, Jagannath Shankarsheth, Cowasji Jehangir, Bhau Daji Lad, Bhagwanlal Indraji, Dorab Tata, Krishna Raj Pandit and Premchand Roychand. The most recent collections received were books from Madhu Limaye, Justice Lentin and Y.M. Kulkarni.