Stores across Britain will not have the new card readers in place by tomorrow and companies are being warned that they could be held liable for credit card fraud.
Around 770,000 out of 860,000 tills in the UK have already installed the card readers, according to payments association Apacs.
The Independent reports that a number of large retailers, including BHS, John Lewis, Clinton Cards and B&Q, have not yet switched all their tills over to the chip and pin technology.
Apacs spokeswoman Sandra Quinn told the newspaper: "It is a mixed picture - most retailers have recognised that customers want this technology, but not all tills have been converted."
From Valentineâs Day, shoppers are required to use their pin (personal identification number) to make purchases with their debit or credit cards in stores and could be turned away if they cannot remember it.
However, a poll by analyst TNS Financial & Professional Services suggests that more than five million Brits still do not know their pin number and one in ten of those surveyed said they were not aware that tomorrow marks the deadline for chip and pin technology.
Chip and pin technology aims to reduce card fraud levels in the UK and has also been adopted by a number of other European countries. There are an estimated 128 million chip and pin cards now in circulation in Britain.