The lawsuit was filed Friday in U.S. District Court in Delaware. It involves two patents that cover "cardless payment" systems, which allow consumers to pay for transactions using a telephone number and a security code.
PayPal executives could not immediately be reached for comment. A representative for Bank One, the corporate parent of First USA, said the company does not comment on pending litigation.
According to the U.S. Patent and Trademark Office, the patents in question were issued to Kurt M. Campisano in May 2001 and January 2002.
PayPal's service allows consumers to make and accept payments over the Internet without using credit cards. eBay announced in July that it wouldthe company for $1.5 billion.
PayPal is facing other legal problems, including otherand class-action lawsuits from customers who claim that the company illegally froze their accounts.