Manuscripts department's collection is second to none as it holds 9,500 items (2,500 musical manuscripts, 5,000 letters and documents, 2,000 rare photographs of the 19th - early 20th centuries).

Musical manuscripts (autographs and copies) of Russian composers of the 19th and 20th centuries are prevalent in this collection which keeps autographs by M.Mussorgsky, N.Rimsky-Korsakov, P.Tchaikovsky, A.Glazunov, M.Glinka, A.Borodin, A.Dargomyzhsky and others. There are manuscripts by foreign composers (Beethoven, Mozart and others). The collection holds handmade scores and instrumentations of operas by F.Araia, B.Galuppi and certain other composers staged in the 18th century in Russia. Hand-written scores of Russian and West European church songs of the 15th-18th centuries also make part of the collection.

There is a vast collection of letters of Russian musicians - M.Balakirev, A.Borodin, A.Glazunov, K.Davydov, C.Cui, A.Lyadov, N.Rimsky-Korsakov, A.Rubinstein, A.Serov and foreign ones - L.Beethoven, L.Cherubbini, R.Wagner, I.Brahms, P.Viardot, Ch.Gounod, F.Liszt, F.Mendelson, C.Saint-Saens, J.Field and others.

Musical score publications signed by prominent composers and musicians are also kept in this collection.

A special mention should be made of an archive of photographs of teachers and alumni of the St.Petersburg Conservatoire, composers, performers from Russia and from abroad (1860-1917) made by such well-known photographers as Sh.Bergamasco, A.Lorentz, A.Pazetti, K.Bulla, V.Yasvoin, A.Otzup, E.Mrozovskaya, K.Fischer and others.

The department actively researches manuscript materials and publishes its gains. Thus, "Petersburg Musical Archive", collected scientific works, was published in St.Petersburg in 1997; a reference book entitled "Autographs of N.Rimsky-Korsakov in the St.Petersburg Conservatoire Library Manuscript Department" is ready for publication. Conferences on musical manuscripts heritage (St.Petersburg Conservatoire Library Manuscripts Department Readings) have been conducted regularly since 1996 with manuscript experts of major musical institutions of Russia.