Film rental firm Blockbuster is to rent high-definition DVDs only in the Blu-ray format at 1,450 US stores.
Blockbuster says customers are opting for Blu-Ray
The move is viewed as a blow for the rival Toshiba-backed HD DVD format - which has been battling against the Blu-ray format, supported by Sony.
Blockbuster said that consumers have chosen Blu-ray over HD DVD in the 250 stores where both were available.
The limited choice of titles in the HD DVD format was also a factor in focusing on Blu-ray, Blockbuster said.
"The consumers are sending us a message. I can't ignore what I'm seeing," Matthew Smith, senior vice president of merchandising at Blockbusters, told the Associated Press news agency.
Mr Smith added that most studios were offering films on Blu-ray, with the exception of Universal which has been supplying films on HD DVD alone.
The North American HD DVD Promotional Group said Blockbuster's move was short sighted, and had been prompted by the success of films released exclusively in the Blu-ray format in early 2007 such as Casino Royale and Spider Man.
"I think trying to make a format decision using such a short time period is really not measuring what the consumer is saying," said Ken Graffeo, co-president of the group.
The HD DVD format will still be available at Blockbuster in 250 of its stores as well as via the internet.