Knox was convicted of the brutal murder in 2009.
"I am paying for my life for something I haven't done. I lost a friend in the worst and most inexplicable way," said a trembling Knox, who had to compose herself before continuing.
The Seattle exchange student, 24, wearing a blue tunic and speaking in Italian, replied to the judge's statement that she didn't have to stand by saying, "I'm so scared it doesn’t matter if I stand or sit."
Knox pleaded her innocence and that of her Italian boyfriend, Raffaele Sollecito, who was also convicted of the killing. "I'm not the person they've portrayed me to be. They say I will escape. I won't escape. I just want to go home. I'm innocent and we didn't do it," said Knox.
She added, "I was terrified when Meredith's body was discovered because I thought that it could have been me. Had I been there and not been with Raffaele I could have been killed, too. … Meredith was my friend."
In her declaration of innocence, Knox stated, "I did not kill. I did not rape. I did not steal. I wasn't there. I wasn't there at the crime."
'Amanda and Raffaele Free'Preceding Knox on the stand, Sollecito spoke in slow, measured terms and said of himself and Knox, "We had strong feelings for each other. We had the opportunity that evening to be together, and we wanted to cut the world out and just spend time together."
He also said, "People have asked for the life in prison or the death sentence. The truth is, in prison at the end of each day, I die. I would like to leave a gift for the court. It's a little bracelet and on it it says 'Amanda and Raffaele Free.' "
He said now is the time to remove the bracelet.
The pair have been in La Cappane prison more than 1,400 days. Their appeal has focused largely on DNA evidence found on a knife and on a bra clasp belonging to Kercher, and Monday's statements by Knox and Sollecito follow a dramatic week of closing arguments.
Prosecutors requested that the couple's sentences – Knox's of 26 years and Sollecito's for 25 years – be increased to life.
Victim's Family SpeaksJust hours before the expected verdict, the family of Meredith Kercher told reporters it was hard for them to watch so much focus on Knox rather than Meredith.
"It's been difficult to keep her memory alive," said Meredith's sister, Stephanie.
Meredith's mother Arline Kercher said she had faith in the Italian justice system. "In the end it's not what I want or we want, it's about the evidence. And we want to see some justice done for Meredith."
The case has now gone to two judges and six jurors. The court said a decision would be returned no earlier than 8 p.m. local time Monday.
When the verdict is issued, the judge warned the courtroom Monday morning, "This is not a football match. I don’t want to hear cheering or comments. I want silence and respect for the victim."
Reporting by DANA KENNEDY