Helms, a five-term senator who will turn 80 in October, delivered a rare televised speech on WRAL-TV -- the same station he worked at as a political commentator -- a job he used to help jump start his political career almost 30 years ago.
Helms increasingly has suffered from medical problems in the past few years, including prostate cancer. He has had to rely on a motorized scooter to make his way through the Capitol Building.
"`There is one inescapable reality that no man can ignore, and that is that time takes a terrific toll, which is of an increasing nature with those who live many years,'" Helms said, quoting from the farewell speech of now-deceased Sen. Sam Ervin Jr., D-N.C.
Ervin announced in December 1973 -- less than a year after Helms entered the Senate -- that his age would stop him from seeking another term. Ervin, who served 20 years in the Senate, was 69 when he announced his decision.
"I would be 88 if I ran again in 2002 and was elected and lived to finish a sixth term," Helms said, continuing to model his speech on Ervin's address. "And this my family and I have decided unanimously that I should not do. And, ladies and gentlemen, I shall not."
Helms' announcement silenced months of speculation by both Democrats and Republicans wondering if North Carolina's senior senator would choose to run for a sixth term.
His withdrawal from the 2002 race leaves the field open to possible Republican candidates such as Elizabeth Dole, wife of 1996 Republican presidential candidate Bob Dole; Lauch Faircloth, a former senator who lost to Sen. John Edwards, D-N.C., in 1998 and Richard Vinroot, the 2000 Republican gubernatorial candidate.
Democrats eyeing the seat include Secretary of State Elaine Marshall, N.C. Rep. Dan Blue, D-Wake, and Mark Erwin, a Charlotte businessman.
Helms is the longest-serving senator in N.C. history. He has spent 28 years in the nation's capitol, focusing on agriculture and foreign policy. He chaired the Senate Foreign Relations Committee from 1995 until earlier this year when Sen. James Jeffords, I-Vermont, left the Republican Party, providing the Democrats with a majority.