The music for The Hunt for Red October was composed by Basil Poledourus. He has also composed the score for Red Dawn, Free Willy, and Conan the Barbarian.
The majority of the music is very Russian. It ranges from solemn to intense as the film progresses. The opening titles are set to the Hymn to the Red October. Poledourus wrote this for a full orchestra and a Russian choir. It provides a feeling of sadness, excitement, and pride all in the first few minutes of the film.
Throughout the film are other snippets of music to provide mood where necessary. The only piece used that was not written by Poledourus was the National Anthem of the Soviet Union. It is sung by the crew of the Red October as it begins its voyage.
Hollywood.com has recently conducted an interview with Basic Poledourus, read it here: http://www.hollywood.com/pressroom/interviews/bpoledouris/bpoledouris.html.
Hymn to the Red October (RA)
The National Anthem of the USSR (MIDI)