The channels, which are both joint ventures between BSkyB and the US-based Television Networks, spend around £1 million a year on above-the-line advertising.
Leith London is the incumbent on the Biography Channel creative business, having won the account in 2002. The agency created a television commercial for the channel in February last year .
Media buying for both channels is handled by Equinox, while Monkey Communications is responsible for media planning.
The review coincides with a change in strategy for the Biography Channel, which has switched from pure brand awareness to a more programme-focused approach.
A number of agencies are understood to have been approached by the channels, although Leith London has not been invited to repitch.
Nicki Harris, the marketing director for both channels, said: "Our media arrangements have been in place for three years and it is just time for a review." Harris said the review would not affect the History Channel's creative agency, Cuba, which has worked for the channel for the past three years.
In May, the History and Biography Channels became the latest in the Sky Media portfolio to run interactive advertising.
Sky Digital's seven million viewers can now use their remote controls to access product information or order a sample while watching interactive TV ads on either of the two channels.
Toyota was the first advertiser to use the medium, with a campaign for the Avensis and Verso that enabled users to request brochures.