As many as half a million elderly people may be being abused, a House of Commons report says.
Elderly abuse has a low profile
An inquiry found two-thirds of the cases of abuse occur in people's own homes.
It took the form of sexual, physical and financial abuse, neglect and over-medication, the Commons Health Committee said.
The government's Healthcare Commission pledged to tackle the mistreatment of the elderly.
The committee said: "Abuse of older people is a hidden, and often ignored, problem in society."
Where abuse of the elderly happens
67% - in their own home
12% - nursing homes
10% - residential care
5% - hospitals
4% - sheltered housing
2% - other locations
It accepted that uncovering the exact number of elderly people being abused was difficult, but called on the Department of Health to clarify the full extent of the problem.
As well as occurring in their own homes, abuse also happened in nursing homes, residential care, hospitals and sheltered housing, MPs said.
The elderly did not report much of the abuse because they were frightened, embarrassed or unable to, the report found.
Carers often took no action because they lacked training in identifying abuse or were ignorant of reporting procedures.
The committee demanded the government look at how NHS organisations which deal with older people are inspected.
It said the practice of over-prescribing medication as a way of managing patients had to be tackled.
The report said care home residents should have their medicines reviewed at least every three months.
The committee added: "We call for mandatory training in the recognition, reporting and treatment of elder abuse for those professionals working and caring for older people."
The government's national service framework for the elderly was criticised for failing to set standards for the protection of adults by local authorities.
The committee also said the registering of domiciliary care workers was a "matter of the utmost urgency" and that certification of death was of "particular concern".
It noted the Dr Harold Shipman murder case had highlighted the potential for abuse of the system.
The report added: "Certification of the cause of death of a resident in a care home owned or managed by a GP, or a close relative, should be performed by a GP other than the owner or manager."
The Healthcare Commission, set up by the government to monitor standards in health services, pledged to tackle abuse.
Its chairman Sir Ian Kennedy said: "We take the abuse of older people very seriously. Older people can be some of our most vulnerable citizens and far too often can find it hard to speak out."
It is reviewing older people's services in England, including asking the elderly for their views, and a national report is due next year.
Jonathan Ellis, at Help the Aged, said: "At present, little is known about the prevalence of elder abuse, particularly the abuse of older people in their own homes.
"We urge the government, the health service, local authorities and primary care trusts to act quickly and collectively to end elder abuse."
Health minister Stephen Ladyman said: "This government has worked hard to tackle the abuse of older people and has made it clear that there will be no hiding place in the care system for those who abuse vulnerable adults."
Paul Burstow, a Liberal Democrat member of the Commons Health Committee, said: "The report must act as a wake-up call for a complacent government.
"Elder abuse is still a taboo and is all too often a case of 'out of sight, out of mind'. It's high time ministers stopped dithering and took this issue seriously."
Simon Burns, for the Conservatives, said: "For too long, elderly abuse has been the problem that dare not speak its name."
Nadra Ahmed, chairman of the National Care Homes Association, said: "While great strides have been made in the care sector to monitor standards of care - not least in independent residential care homes run by our members - there is still an obvious need to look at the wider circumstances in which abuse can occur, and particularly the steps that can be taken to protect older people in their own homes."