The company learned about the security breach Tuesday from the U.S. Secret Service and began investigating the breach with the agency and a team of forensics experts.
While it knows that customers were exposed, it doesn't know how many, when it happened, or which restaurants were affected.
The company is working with credit card companies to determine which cards may have been affected.
All P.F. Chang's restaurants are now using manual credit card imprinting devices to process card payments while the investigation continues. There are 209 P.F. Chang's restaurants around the country.
P.F. Chang's China Bistro, based in Scottsdale, Arizona, owns its namesake restaurants and Pei Wei Asian Diners. The company was taken private in 2012 by Centerbridge Partners for about $1.1 billion.
A wave of data breaches at other major U.S. corporations is putting consumes on alert and raising awareness about how vulnerable the system is.
Late last year, thieves stole 40 million credit and debit card numbers from customers shopping at Target (TGT) stores. Personal information of about 70 million Target customers was also taken. Other companies, such as Neiman Marcus, Sally Beauty Holdings (SBH) and Michaels Stores, have also revealed breaches of their systems.