Brighton and Sussex University Hospitals NHS Trust currently has 972 empty posts which need to be filled, giving it a vacancy rate of 11.8 per cent.
Bosses say they are working hard to recruit and keep staff and new workers are due to start in the coming months.
Staff shortages put extra pressure on already overstretched workers at the trust’s hospitals.
They also have a financial impact because it means the trust has to pay for agency or bank staff to cover shifts or wards will be dangerously understaffed.
The highest proportion of vacancies, 429, is in nursing, particularly in speciality medicine.
There are also 322 jobs that need to be filled across the administration and clerical and ancillary support staff groups.
The trust has a turnover rate of 14.3 per cent, which is higher than the national average of 12 per cent.
A report to the trust board said recruiting and keeping staff was a key priority.
Recruitment days have recently been held for healthcare assistants (HCAs) and nurses in a bid to boost numbers and more are planned.
In the latest events, jobs were offered to 29 HCAs and 22 qualified nurses.
Staff have also been recruited from abroad.
Chief nurse Caroline Davies told board members the trust was contacting nurses who had left to come back to work.
About 600 have been approached so far.
The trust is also looking at the reasons why people are leaving, to see if there is a pattern and if anything can be done to tackle it.
There is currently a national shortage of nurses and trusts around the country have been struggling to fill vacancies.
Many nurses are also leaving the profession due to increased pressures and demands.
Student nurse Graeme Stokes, from Brighton, is chairman of the city’s branch of the Royal College of Nursing (RCN).
He said issues around low pay and long hours made it hard to attract people to the nursing profession.
Some nurses are having to resort to using food banks and take on second jobs to make ends meet.
Mr Stokes said: “Staff are are working tirelessly and some are avoiding taking annual leave simply because they have not been able to.
“It all leads down to the problem with recruitment and with trying to bring staff back to the NHS.
“Some have left to go and work abroad while others have joined agencies or private health care.
“The profession is simply not attractive.
“If you are a teenager looking to go to university why would you want to saddle yourself with a £45,000 debt with a starting wage of £22,000?”
The RCN is planning a summer of protests calling on the Government to scrap the one per cent cap on NHS pay.
It is also threatening to hold a ballot for strikes after a poll showed nine out of ten members would support the move.
Unison south east regional organiser Caroline Fife said the high cost of living in Brighton and hove was another factor.
She said: “When the pay is the same then people are going to take other issues into account, such as property, rental and public transport.
“It is cheaper to live in Worthing than Brighton and so given the choice people may opt for there instead.
“There are also uncertainties over Brexit and how it will have an impact on staff from EU countries in the future.”