The NHS organisation in charge of Pinderfields, Pontefract and Dewsbury hospitals received an average of 20 complaints a week between April and September this year.
The Mid Yorkshire Hospitals NHS Trust handled a total of 522 formal grievances made by patients and their relatives over the six-month period.
Issues with clinical treatment was the most common gripe, with nearly half of complaints relating to things like poor nursing care and a lack of pain management.
Bad communication and the attitude of staff were also among the most frequent reasons for lodging a grievance.
However, the figures represent a 28 per cent drop in the number of complaints the trust received over the same time period in 2017.
Addressing the numbers at a trust board meeting on Thursday, director of nursing David Melia said: "We’ve been looking at how we can progress and give patients a better service. It's obviously important that we always treat them with respect and dignity in dealing with their concerns.
"We’ve been trying to deal with complaints at an informal level when they’re first made, so people can be satisfied we’re taking their concerns seriously.
"We're working very hard to meet our obligations around patient experience."
Mr Melia added that the trust's patient advice and liaison service had been moved to a ground floor base at Pinderfields Hospital in a bid to make it more visible and easy for people to access.
The trust says it tries to resolve complaints within 30 days, though on occasion this can be extended with the agreement of the complainant if the issue is complicated.
Of the grievances that have been resolved, 37 per cent were upheld.
A total of 36 per cent were partly upheld, while the remaining 27 per cent were rejected.
522 complaints made to the NHS trust between April and September 2018
720 complaints made to the NHS trust between April and September 2017
37% complaints made between April and September upheld
36% partly upheld
27% not upheld
Local Democracy Reporting Service