June 4, 2006 -- Ann Mercey is afraid to leave her home, because she's waiting to hear from her daughter Ashley, 15, who's been missing for two months.
"It's just horrifying it's horrifying not knowing where your child is," Mercey said. "It's like a nightmare, and I just want to wake up from it."
Ashley wasn't living at home when she disappeared. She's been in group foster homes for three years because authorities decided she needed more supervision.
"I believe if it was somebody else's kid, they would be looking for them," Mercey said, "like with the amber alert and everything."
Ashley is one of thousands of foster children missing across the country -- no one knows exactly how many.
California, Tennessee and Michigan have all admitted they had lost track of children in their care. Florida has one of the highest numbers, with 648 missing children.
"It's a very serious concern," said Millicent Williams of the Child Welfare League of America. "One of the complications in addressing this problem is the lack of sufficient social workers available to really track children. It's also the lack of a computerized systems within agencies to do an accurate tracking of kids."
Kimberly Foster knows that all too well. She moved to her first foster home when she was eight and ran away six times to live on the streets of Miami.
"I was abused," she said. "I was raped."
Social services finally found her in the hospital -- after she tried to kill herself
"I was neglected," she said. "I was belittled. There were times I just didn't think I was worth living. I didn't think I was worth having a life to live. I was very depressed. I didn't feel wanted."
Room for More Improvement
Child advocates say conditions have improved over the past few years -- after some shocking cases brought the issue into the spotlight, including the 2002 murder of 4-year-old Rilya Wilson in Miami. It took Florida social services 15 months to notice she was gone.
"I think that the state takes their job as a parent very seriously," said Florida Department of Child Services commissioner, Darlene Dunbar. "Can we improve? Absolutely."
A few states, including California and Michigan, have put up Web sites with photos of missing foster children. Florida has been working to strengthen rules for caseworkers after an investigation found some failed to visit foster care children monthly as required and falsified records to cover it up.
There are now state supported programs to help foster kids train for jobs and college.
Thanks to one of them, Foster is now on a scholarship at Miami Dade College -- a dream Anne Mercey holds for her daughter, if only she could find her.
ABC News' Gigi Stone originally reported this story June 3, 2006, for "World News Tonight."