The US lawmaker shot in the head in Arizona was removed from a ventilator on Saturday and is breathing on her own through a tube inserted into her windpipe, the University Medical Center in Tucson, announced.
Democratic congresswoman Gabrielle Giffords, who survived despite being shot through the head from point-blank range a week ago, remains in critical condition.
"A surgical procedure (tracheotomy) was performed this morning on the Congresswoman to replace the breathing tube that ran down her throat with a tracheotomy tube in her windpipe, protecting her airway and freeing her from the ventilator," the hospital said in a statement posted on its website.
"Her recovery continues as planned," it said. Surgeons also inserted a feeding tube.
Six people died, including a federal judge and a nine-year-old girl, and 14 were wounded in the burst of violence a week ago outside a Tucson supermarket, where Giffords was holding a public event with her constituents.
Giffords, 40, opened her eyes for the first time minutes after President Barack Obama visited her on Wednesday.
Alleged gunman Jared Loughner, a 22-year-old local resident, is in custody.
The youngest victim of the Tucson shootings was laid to rest on Thursday, a day after Obama, at a Tucson memorial service, hailed the 9-year-old as an inspiration to US politicians to heal their poisonous divisions.
Christina Taylor Green has become the heart-breaking public face of the attacks which unleashed a wave of soul-searching about America's political culture.