A study into homeless kids has shown more than 15,000 young people under 16 leave home every year.
Many run away because of violence, neglect or abuse by their parents.
Once these children leave home, many of them beg and steal, and many said they were beaten up, but they're too scared to ask the police to help them.
The Children's Society, which did the research, said its biggest worry is that kids who run away have nowhere safe to stay once they leave home.
The charity says a network of emergency care centres across Britain are needed to help protect vulnerable children.
A quarter of the children who had run away said they did it because their families had broken down. Others said they didn't get on with their parents or were worried about violence in the home.
Over half of the children who leave home each year are girls, the study found.