A cassette single is a recording of a single song sold on a compact audio cassette. Record companies introduced this sales format in the 1980s. At that time, vinyl record album sales were declining in favor of cassette recordings; the cassette single was introduced to replace the vinyl 45 record in a similar way.
The sales of cassette singles did not exceed vinyl single sales to the same extent as cassette albums had. As compact disc players became more common, cassette singles were for the most part replaced by CD singles.