More than 18,600 parking penalties were issued by three hospitals during 2010, according to consumer group Which?.
Research revealed that the University Hospitals Birmingham trust - which runs three hospitals - issued 18,651 fines in the 12-month period, the equivalent of 51 per day.
Leeds Teaching Hospitals, the second-worst offender, handed out 9,008 tickets.
The coalition government overturned a Labour pledge to ban the charges, claiming that such a move would not be practical. The fees were scrapped in Scotland three years ago while they will come to an end in Wales later this year.
Richard Lloyd, executive director of Which?, said: “Our research shows if hospitals are going to develop patient-focused policies for the future, car parking certainly needs to be on the agenda.”
NHS Confederation deputy director of policy Jo Webber said: “This report from Which? makes some perfectly sensible points about how NHS organisations could improve the way they provide car parking at their sites.
“It is important that patients or visitors who chose to use their cars to attend hospital understand how the system works, how to pay and are aware of any exemptions they might benefit from.
“In our own report on the issue Fair for all, not Free for all, the NHS Confederation argued that charging for parking was an important way of ensuring that hospital spaces were not being abused as well as covering the costs of running car parks, but also made the case for easily understood, convenient and fairly enforced car parking at NHS sites.
“We have also said our members should look at the kinds of concessions they offer for people who have long-term conditions or to the parents of sick children.
“Ultimately, anything which can improve the public’s experience of the NHS is to be welcomed and getting parking right most certainly can contribute to that.
“But it does need to be remembered that NHS organisations will have transport plans, which include buses, the ambulance service, cycling and walking to the site - the most important thing is to get the balance right between different forms of transport so that everyone can access NHS services in as convenient and hassle-free way as possible.”