Currys, Dixons and PC World are to stop stocking analogue televisions and will instead promote "integrated" sets with built-in digital Freeview tuners.
Parent company DSG International suffered poor sales at Christmas
The chains said more than 90% of the TVs they sold were already digital.
The move was welcomed by Digital UK, the body managing the analogue switch-off, which will finish in 2012.
"Retailers of all sizes have a vital role to play in ensuring their products and their customers are ready," Digital UK chief executive Ford Ennals said.
A major push to inform viewers about the move to digital began last year, when Whitehaven in Cumbria became the first area to have its analogue signal switched off.
The Scottish Borders will be the first full geographical region to lose its analogue signal, starting on 6 November 2008. The rest of the UK will follow suit over the next four years.
"We believe that it is appropriate to ensure that our customers are able to select from a future-proof range of televisions," said Currys managing director Peter Keenan.
"Integrated digital televisions are relatively simple to operate, offer superior technology and are an important window on the digital future."
The Digit Al character was used to promote Whitehaven's switchover
The shops will also stop selling DVD recorders featuring only analogue tuners.
The move comes just over three years after Dixons announced it would no longer stock video cassette recorders, another sign of changing times in technology.
The parent company of the three chains, DSG International, admitted earlier this month that its profit margins in the run-up to Christmas had been lower than expected. It had cut prices of goods such as flat-panel television sets to drive demand.