The trust which runs Lincolnshire's main hospitals has been placed in financial special measures by the NHS.
United Lincolnshire Hospital NHS Trust (ULHT) has developed a deficit of £30.7m since April.
A director has been appointed by NHS Improvement after the trust predicted an overspend of £75m by the end of this financial year.
The improvement director will now work with the trust to develop a recovery plan to tackle the deficit.
Welcoming the move, UHLT deputy chief executive Kevin Turner said the trust faced "one of the biggest financial challenges in the NHS".
"We know that there are many factors which are causing the deficit, which include a lot of our services being less efficient than they could be, staffing gaps that are routinely filled with more expensive temporary (agency) staff, and the challenges of providing services over a large geographical area," he said.
"Our recovery plans will need to address these factors and more."
The trust, which runs Lincoln County, Grantham District and Boston Pilgrim hospitals, was placed back in special measures by the Care Quality Commission (CQC) after a report in April highlighted concerns over the quality and safety of patient care.
It was previously in CQC special measures between October 2103 and March 2015.