Staff shortages have forced doctors to refuse new admissions for short periods to children's wards at Cheltenham General and Gloucestershire Royal.
A spokeswoman for Gloucs Hospitals NHS Trust said with paediatric services split over two sites, shortages of key staff meant closures were necessary.
"The health community has made the decision to move children's inpatients to Gloucs Royal," she said.
"The trust believes the problem will cease when there is just one centre."
Guy Routh, the trust's medical director, said it was recruiting more specialist staff and they were due to start soon.
"It is unfortunate for parents and we are trying to minimise the effect these closures have on them."