Former US fugitive Eric Rudolph has pleaded guilty to carrying out the 1996 Olympic bombing as well as other blasts in Atlanta and Alabama.
Eric Rudolph has agreed a plea bargain
Rudolph, 38, admitted to the crimes first in a court in Birmingham, Alabama, and then later in Atlanta.
Last week Rudolph agreed a plea bargain that means he receives four life sentences without parole but avoids the death penalty.
The four blasts killed two people and injured more than 120 others.
In Birmingham, Alabama, Rudolph admitted to being behind a 1998 abortion clinic bombing that killed a police officer.
In Atlanta, Georgia, he admitted to attacks there, including the blast during the 1996 Olympics that killed a woman and injured 100 and an attack on a gay nightclub.
The fatal blast marred the Olympic Games and led to fears of US domestic terrorism.
Rudolph is suspected of following a white supremacist sect that is against abortion.
BOMBINGS BLAMED ON RUDOLPH
1996: Atlanta Olympic games, 1 dead
1997: Atlanta gay nightclub
1997: Atlanta abortion clinic
1998: Birmingham abortion clinic, 1 dead
After being identified following the attacks, he went into hiding in the North Carolina mountains, avoiding capture for five years.
It is thought people in the area sometimes left food for him or did not inform on him, despite there being a substantial reward.
Rudolph arrived at the federal court in Birmingham in a car surrounded by 10 marked and unmarked police vehicles, the Associated Press reported.
He was said to be shackled and wearing a red prison jumpsuit and a white T-shirt with sleeves rolled up to the shoulders.
When asked by the judge if he planted the bomb outside the abortion clinic he replied: "I certainly did, your honour."
The attack on the New Woman All Women Health Care clinic on 29 January 1998 killed Robert Sanderson and seriously wounded nurse Emily Lyons.
Ms Lyons, who was in court, expressed disappointment at Rudolph's confession.
"He sounded so proud of it," she said. "I feel he is not being punished enough for what he did."
Domestic terrorism fears
Eric Rudolph first came to the attention of investigators after a lorry registered in his name was spotted leaving the scene of the Birmingham explosion.
It was the first bombing with which he was charged, and from that links were drawn with the Olympics attack two years earlier.
After he was identified, Rudolph slipped away into the mountains of North Carolina.
A former soldier, he used survivalist techniques to live off the land for more than five years, while he was on the FBI's list of 10 most-wanted fugitives.
In May 2003 he was captured after being seen scavenging for food in North Carolina.
In the Olympic bombing, Rudolph is suspected of hiding a device in a knapsack which he then placed among the crowds Atlanta's Centennial Olympic Park on 27 July, 1996.