The music is downloaded as a universally-compatible MP3 file, which is not encoded with digital rights management (DRM), so the music will play on any MP3 player, including iPods.
Owner Gcap Media, which also owns Capitalradio.com and xfm.co.uk, has launched the push to drive traffic to the site (www.classicfm.com). It will help to build its CRM database of 400,000 subscribers.
The radio station is pushing listeners to the site, whose daily download is currently its most popular part.
A new track will appear every day in February and March. Members can listen to every piece of music before downloading it if they like it.
The promotion is accessed via the home page and is open to those who sign up to 'Behind The Music'. This provides access to a newsletter with content relating to the radio station and classical music.
The download offer is being run in association with Windows Vista, the new operating system launched last month.
GCap Media account manager Tim Ferris commented: "This genuinely free online offer is part of a focus on becoming the number one destination for entertainment."