Inspectors in England have investigated over 6,000 concerns about childminders and nurseries and prosecuted four child carers in a year.
Ofsted says the majority of carers are suitable
There were 900 complaints about unregistered childminders - and 49 carers' registrations were cancelled.
The statistics, from April 2003 to March 2004, were released by the Office for Standards in Education (Ofsted).
But the education watchdog stressed that the vast majority of carers were providing suitable care for children.
The education watchdog has the power to cancel or suspend the necessary registration to provide childcare and to prosecute a nursery owner or childminder if they have committed an offence.
There are 118,000 registered childminders and nurseries in England and Ofsted receives approximately 120 complaints a week.
It is not clear whether those figures relate to individual cases or include several complaints about one particular carer.
After following up the complaints inspectors cancelled the necessary registration for 49 care providers and prosecuted four.
The chief inspector of schools, David Bell, said the figures related to the care of some 1.4 million children in England and, in relative terms, the 6,250 complaints last year represented "a very small number".
Mr Bell said the complaints typically covered issues such as the behaviour of carers, the safety of the premises and the type of food served to children.
The Ofsted report cited one case where a childminder's registration was cancelled after inspectors received information from social services that her son was being investigated for alleged abuse of his own child.
David Bell stresses the majority of carers offer suitable care
The carer refused to stop her son visiting when she had children in her care.
Another case detailed the prosecution of an unregistered childminder, whose registration had previously been cancelled due to poor standards of care.
She was looking after 14 children in a cluttered and dirty home and did not know all their full names or have contact number for many of the parents.
The Ofsted report was published weeks after a BBC undercover documentary revealed bad practice in some private nurseries.
"We take matters about children's safety very seriously and through our work in this area we help protect children from people who are unsuitable to care for them," said Mr Bell.
"We are not able to monitor childminders and nurseries 24 hours per day, so it is important that anyone with a concern should contact us without delay so our inspectors can investigate to ensure that child carers meet national standards."
"Parents should be assured that the large majority of childminders and nurseries provide suitable care for children."
Ofsted recommends that, before deciding whether to send their child to a nursery or childminder, parents read the inspection report on the Ofsted website, visit the provider and ask questions about the care provided.
Rosemary Murphy from the National Day Nursery Association said parents should be reassured by the role Ofsted had, but admitted there was cause for concern.
"We'd like to think there would be no complaints.
"But until we have a workforce that is properly trained and paid, then I think we're going to have these issues for quite some time to come."