The retail giant Walmart will be attaching electronic ID tags to some of the clothing it sells.
The Wall Street Journal has reported that the so-called "smart tags" are part of a system to keep track of a store's inventory.
Wal-Mart said the tags will help reduce theft and counterfeiting, the latter particularly affecting prescription medicines.
Walmart officials at the company's corporate headquarters in Bentonville, Ark., refused to say how much the retailer is spending on the new technology.
However, some privacy advocates have concerns. Even though the tags can be removed from clothing, they can't be turned off. Anyone could pick up signals from them.
For example, if a tag is thrown into a trash can, anyone with a handheld scanner can find out what a person recently bought.
Walmart believes the tags represent cutting edge technology that could one day replace the bar code. The radio frequency information or RFID tags will be placed in about 3,700 Walmart stores next month.