The number of children going missing from foster care rose by almost a fifth in the last year, according to the latest report from Ofsted.
It found there were 5,055 children recorded as missing in 2014-15, up 19% on the previous year.
Local government leaders said the rise was 'worrying' but was also a sign that identification and reporting of such incidents were improving.
Ofsted's 'state of the nation' report also reveals that:
• There were 85,890 children and young people placed in foster care, an increase of 2% on 2013-14
• There were 36,890 fostering households, a decrease of 1%, while the number of family and friends households increased by 6% to 4,145
• The number of young people still living with their foster carers after reaching the age of 18 increased by 2%
For the first time Ofsted also asked services for data on child sexual exploitation (CSE) and children in foster care.
It found 3% of children and young people were reported as being at risk of CSE during the year while 1% were reported to be subject to it.
Eleanor Schooling, Ofsted’s national director for social care, said the slight rise in children being placed in foster care again showed that it continues to be a valued choice for vulnerable young people.
Commenting on the increase in numbers going missing, she added: 'While the rise may be a result of better recording and awareness from services, this remains an issue of concern given the grave risks associated with children who go missing.'
Cllr Roy Perry, chairman of the Local Government Association's children and young people board, said: 'Councils work hard to ensure children are settled with foster carers, and any child missing from care for any length of time is a concern for everyone.
'While the increased numbers of children going missing is worrying, it is also a sign that identification and reporting of these incidents is continuing to improve, reflecting the heightened awareness of the dangers that this behaviour can pose.'