The U.K. unit hopes to receive creditor approval to close at least 26 of its 105 stores in England, Wales, Scotland and Northern Ireland.
Steve Knights, managing director of Toys R Us UK, said the warehouse-style stores opened by the retailer in the 1980s and 1990s have proven "too big and expensive to run", adding that "newer, smaller, more interactive stores in the right shopping locations" were trading well.
Toys "R" Us Inc. has begun the process of seeking creditor support to restructure its United Kingdom arm.
Retail analyst Richard Hyman said: 'The vast majority of United Kingdom retailers have too many stores.
The retailer has put forward proposals to shut 26 of its United Kingdom premises as part a a company voluntary agreement (CVA), putting up to 800 jobs at risk.
In a statement released today, the company said that it plans to revamp its business in response to "evolving needs of customers in today's United Kingdom retail market".
"The decision to propose this CVA was a hard one, but we determined it is the best path forward to make essential changes to the business".
The chain has been loss-making for seven out of the past eight years, with the most recent accounts filed at Companies House showing an operating loss of £500,000 on sales of £418m in the year to January.
Mr Knights said: "Like many United Kingdom retailers in today's market environment, we need to transform our business so that we have a platform that can better meet customers' evolving needs".
The firm said it anticipated redundancies among its workforce of 3,200 but did not give a specific number.
It is unclear whether the retailer's landlords and creditors will support the CVA proposal, the same process used by BHS to exit loss-making stores during its demise. "Our teams will continue to play a key role in turning our business around".
The British business has also needed approval from its American owners, who have been going through their own bankrupcy protection procedure to refinance their debts, securing a £3bn finance deal in October.