New data for October 2019 has revealed that the Calderdale and Huddersfield NHS Foundation Trust failed to meet expected standards on A&E waiting times.
The NHS operational standard for A&E waiting times dictates that 95% of patients should be admitted, transferred or discharged within four hours of arriving.
Calderdale And Huddersfield NHS Foundation Trust.saw 87.8 per cent of A and E patients were seen at the trusts hospitals within four hours.
Performance data for October 2019 shows that of the 11 trusts surveyed in Yorkshire, just two - Barnsley Hospital NHS Foundation Trust and Sheffield Children's NHS Foundation Trust - met the national operational standard of getting 95% of A&E patients admitted, transferred or discharged within four hours.
Bradford Teaching Hospitals NHS Foundation Trust was the worst-performing trust in October.
Data for Mid Yorkshire Hospitals NHS Trust and The Rotherham NHS Foundation Trust was not available for October.
Bradford Teaching Hospitals NHS Foundation Trust was the worst-performing trust in the region, with just 73.3% of patients attended to within the four hour target window.
The best-performing trust in Yorkshire was Sheffield Children's NHS Foundation Trust, where 97.8% of A&E patients were either admitted, transferred or discharged within the expected four-hour window.
Nationwide, the data has shown that A&E performance is at an all-time low, with one in six patients waiting longer than four hours in A&E in England during October - the worst-ever performance since the four-hour target was introduced in 2004.
Sheffield Children's NHS Foundation Trust was one of just two trusts in Yorkshire that met the national NHS target for A&E waiting times.
The health service has also missed out on a number of other targets, including how long people wait to start planned treatment and waits for cancer care.
In March, NHS England announced proposals to scrap the key targets for patients to be seen in A&E within four hours, or to receive an operation within 18 weeks.
The Royal College of Surgeons and the charity Versus Arthritis, however, called on party leaders to safeguard the 18-week target.
Professor Derek Alderson, president of the Royal College of Surgeons said: "It just isn't acceptable for so many people to languish on these lists, with deteriorating physical and mental health as they wait for treatment."