A 27-BED ward at Dewsbury District Hospital is to close because of a shortage of nurses.
Ward 5, which deals with patients who need urgent treatment, is being shut at the end of the month until more nurses can be recruited.
Nurses in the ward are being sent to other wards.
But staff now fear it will mean longer waits for treatment for patients.
The ward has shut at a difficult time, because winter normally brings an influx of elderly medical patients suffering from chest complaints.
Shortage of bed space traditionally has a knock-on effect on scheduled operations, which sometimes have to be cancelled to cope with the influx of patients.
A staff member, who did not want to be named, said: "The bed crisis is bad enough, as there was never an empty bed on Ward 5, but now winter is coming."
There are fears that specialist services on the ward - rheumatology and dermatology - could now be halted.
A statement on behalf of the Mid Yorkshire NHS Trust said: " We are recruiting nursing staff to work on the medical wards at Dewsbury Hospital.
"However, until we have recruited extra nurses we are unable to keep all our medical beds open.
"One ward is therefore being temporarily shut and all nursing staff from it will move to other medical wards in the hospital.
"Since the trust was created 18 months ago we have invested a considerable amount of resources to develop services at Dewsbury.
"We are committed to providing high-quality services for the people of Dewsbury and plan to re-open Ward 5 at the earliest opportunity," the statement added.