Hospitals in England made a record £174m last year in charging for parking, an investigation has found.
The figure for 2016-17 was 6% up on the previous financial year, data collected by the Press Association under the Freedom of Information Act showed.
The figures also showed a growing amount of revenue being made from fines - up by a third to £950,000.
The system has been branded a "tax on sickness", but hospitals said charging was needed and money made reinvested.
Car parking is largely free in Scotland and Wales.
PA obtained data from 111 hospital trusts out of the 120 they approached on charges for patients, visitors and staff.
The results also showed:
- Half of all trusts charged disabled people for parking in some or all of their disabled parking spaces
- The Heart of England NHS Foundation Trust took the most money - over £4.8m
- Two-thirds made more than £1m in each of the last three years
- The most expensive place for a one-hour stay was the Royal Surrey County Hospital in Guildford at £4
Liberal Democrat health spokesman Norman Lamb said: "The vast sums of money that hospitals are making from parking charges reveal the hidden cost of healthcare faced by many patients and their families.
"Hospital car park charges amount to a tax on sickness, with people who are chronically ill or disabled bearing the brunt."
Parking 'unfair and unnecessary'
Labour shadow health secretary Jonathan Ashworth, added: "Hospital parking charges are an entirely unfair and unnecessary burden, which disproportionately affect the most vulnerable people."
Rachel Power, chief executive of the Patients Association, said the current state of NHS finances meant it was sometimes hard to blame hospitals for trying to find money.
But she said that did not make the current situation acceptable.
"For patients, parking charges amount to an extra charge for being ill," she said.
Hospitals have defended their approach to charging. Those in urban areas believe the parking will be used by shoppers without having a system of charging, while the money raised is used to maintain car parks, grounds and - in some cases - reinvested in patient care.
Concessions are available in many places for those who need to make repeat visits, such as chemotherapy patients.
A Department of Health spokesman said charges were a matter for local hospitals.
But he added: "We want to see them coming up with flexible options that put patients and their families first."