Hundreds had to wait over an hour to be transferred from their ambulance to A&E at Doncaster's hospitals in the last year.
Under official Government guidelines, no patients are supposed to have to wait an hour while they are transferred from the vehicle to the care of the hospital.
But official figures published by the NHS reveal that the target has not been met for over a year.
Statistics were presented to the Doncaster NHS Clinical Commissioning Group at their monthly meeting.
For the 12 month period from May 2016 until April 2017, 205 patients had to endure 60 minute waits.
But health officials say that Doncaster is among the better performing hospitals trusts in Yorkshire.
The number of patients left waiting outside the hospital hit their highest level in January, when 66 patients were kept waiting in their vehicles for more than an hour. The figures came at one of the busiest periods for the hospital.
The most recent figures available were for April 2017, and they showed 21 patients waiting.
That was the third highest figure for the 12 month period, behind September 2016, which saw 28 people waiting over an hour.
David Purdue, Chief Operating Officer at the Trust, said: “This winter was extremely busy for emergency attendance. As a Trust we try and see all those arriving by ambulance within 15 minutes, coming within the top 25 per cent of organisations within the region to achieve this goal.
"If a handover takes slightly longer, this is usually due to do a number of factors such as high attendance within the Emergency Department and therefore it is safer for the patient to remain with paramedics, inside the hospital, until our staff are available."
Ministers last week announced plans to put more cash into accident and emergency departments , with Doncaster promised an extra £975,000 to try to ease pressure on the department ahead of next winter.
This money is part of dedicated funding announced in the Government's spring budget to ensure A&Es can change the way they assess patients to make sure people are given the most appropriate care as quickly as possible, being seen by a trained medical professional and then signposted to be assessed and treated in the most appropriate setting, whether this is in the Emergency Department or in the GP-led Urgent Care Centre, both of which are at Doncaster Royal Infirmary.
Doncaster Central MP Rosie Winterton said: “Any extra money is, of course, welcome to address the pressures we know our A&E Department in Doncaster is facing. But there are still huge strains on our local NHS, particularly with staff shortages which need further additional money to put right.”