NBCユニバーサル・エンターテイメントジャパン
Geneon Universal Entertainment (now NBCUniversal Entertainment Japan) released four audio dramas for the first season of "Index" under the title "A Certain Magical Index Archives" from March 25 to August 21, 2009. The same enterprise released another four audio dramas for the second season from May 25 to August 24, 2011. A drama CD for "A Certain Magical Index III" was released as a bonus for customers who purchased the limited edition volume sets of the series via "Amazon"'s Japanese website.