The number of children running away from care in Suffolk has has risen by 75% in four years, figures show.
Following a BBC Freedom of Information request, the county council said 71 youngsters ran away in 2012, compared to 41 in 2009.
The council had 780 "looked after children" in 2012 and 715 in 2009.
The local authority claimed the increase reflected improved data collection and not necessarily more children running away from care.
David Tucker, associate head of policy at the National Society for the Prevention of Cruelty to Children, said: "Children in care go missing three times more often than other children.
"We know that 55% of children who are accessing support from charities having suffered sexual exploitation were missing or missing from care, so it's a very significant problem.
"You can't do everything and children will run away, but it's really incumbent on those authorities that are acting to care for those children to take all possible steps to stop them, because they are so vulnerable."
Cliff James, interim head of corporate parenting at Suffolk County Council, said: "This is an area that we've particularly monitored over the past four years and we're much more careful about recording these issues.
"Seventy-one is more than we would want, but the ones who run tend to be the ones who have come into care later as teenagers, have suffered abuse and are vulnerable before they get to us.
"I don't think there is a greater level of vulnerability than there was four years ago, but what I can say is that once it happens [with an individual], we get to grips with it fairly quickly."