The Saolta hospital group is predicting that it is facing a deficit of 45 million euro this year.
Its deficit last year was 23 million euro.
The group includes the university hospitals in Sligo, Letterkenny, Mayo, Roscommon, Galway and Portiuncla.
The Saolta University Healthcare Group received 656 million euro in funding for this year.
Having a 23 million euro deficit for 2015, the group received a supplementary budget of 29 million euro at the end of 2015.
Increased patient numbers attending as in-patients, day cases, and at the emergency departments, as well as efforts to reduce the numbers on waiting lists impacted on the hospital group’s finances.
The hospital’s group says dealing with a forecasted 45 million euro deficit for 2016 is a major challenge, with controlling costs a major focus.
Sligo University Hospital, which has 279 in-patient beds, had 1,492 staff at the end of last year, according to its report for last year.
There was 1,425 employed in Letterkenny University Hospital.
A concern has been the cost associated with overtime and the employment of more agency staff.
However, the Saolta group says it is confident that efforts to engage directly-employed HSE staff will show savings.