Bettman made the disclosure at the end of a news conference to announce a partnership between the league and software giant Sun Microsystems.
The 49-year-old Bettman, who has been the NHL's top executive since February 1993, provided no details on the five-year contract extension.
"The fact is, I am under contract through 2008 with the NHL and that arrangement was finalized with the Board of Governors some time ago," he said. "It is not new news."
During Bettman's tenure, the NHL weathered a nearly four-month work stoppage before the 1994-95 season. The league's current collective bargaining agreement expires after the 2003-04 season.
Bettman also oversaw negotiations that resulted in a five-year, $600 million contract with Disney properties ABC and ESPN that returned the NHL to American network television. That pact also runs through the 2003-04 season.