More than 86,000 NHS posts were vacant between January 2017 and March 2017, figures for England suggest.
Statistics from NHS Digital, which collates data, shows the number of vacancies climbed by almost 8,000 compared to the same period in 2016.
Nurses and midwives accounted for the highest proportion of shortages, with 11,400 vacant posts in March 2017.
The Department of Health said staffing was a priority and that more money was being invested in frontline staff.
The data includes job adverts published on the NHS Jobs website between February 2015 and March 2017.
There are currently an estimated 1m full time jobs across the NHS in England.
The latest figures suggest in March 2017 alone there were 30,613 full-time equivalent vacancies advertised on the NHS Jobs website - the highest total for a month since this type of data was first collected in February 2015.
And nursing and midwifery vacancies have topped the list since these figures have been collated.
The data includes adverts for doctors, dentists, administrative, clerical staff and technical and scientific staff. The figures do not include vacancies for GPs or practice staff.
But as other ways of advertising NHS jobs - including adverts seeking overseas applicants - exist, NHS officials say caution must be used when interpreting the results.
Meanwhile, a Department of Health spokesperson said: "We expect all parts of the NHS to make sure they have the right staff, in the right place, at the right time to provide safe care - which is why there are almost 32,400 more professionally qualified clinical staff including almost 11,800 more doctors, and over 12,500 more nurses on our wards since May 2010."
Janet Davies, general secretary of the Royal College of Nursing, said low pay and "relentless pressure" meant many nursing were leaving the profession.
"At the very moment the NHS needs to be recruiting more nursing staff, we learn the number is falling and the NHS finds itself advertising for more jobs we know it cannot fill," she said.
"A lethal cocktail of factors is resulting in too few nurses and patient care is suffering.
"More people are leaving nursing than joining - deterred by low pay, relentless pressure and new training costs.
"For the sake of patient safety, the Chancellor must scrap the cap on pay and help to fill the tens of thousands of vacant nurse jobs."
The RCN says nursing remains one of the lowest paid staff group of all public sector professions.
According to its figures average starting salaries for nurses in London are around £26k and £22k elsewhere.
Why is the NHS short of staff?
The Department of Health says thousands more staff have joined the health service in the past seven years. And it says the seasonal way in which staff are recruited - with more joining between late summer and mid-winter - could account for some of the trends in the report.
Meanwhile, NHS Improvement, which is responsible for overseeing NHS trusts, has a scheme in place to encourage more staff to stay within the health service and Health Secretary Jeremy Hunt has promised more medical student places in the future.
But despite these moves, a number of organisations are concerned factors such as Brexit are denting the confidence of EU staff working in the NHS.
The outgoing chief inspector of hospitals in England, Prof Sir Mike Richards, told the BBC's Today Programme that Brexit posed a threat to recruitment which had to be addressed.
And a recent report by the Health Foundation found that the number of EU nurses registering to work in England had dropped since the vote to leave the EU.
The Department of Health has said EU staff play a "valued" role in the NHS and are a priority in Brexit negotiations.
But the Nursing and Midwifery Council points out that other issues - such as a recently introduced English language test - are also likely to have played a part.
Meanwhile historians argue NHS staff shortages have persisted since the very beginning of the NHS.
They say the list of problems and solutions - including the number of training places for nurses and doctors and a reliance on overseas staff - is likely to be very long.
Danny Mortimer, chief executive of NHS Employers, said employers were working "especially hard" to bring in more nurses.
He added: "We accept that retention is just as important as recruitment to keep vacancy levels low - that is why NHS Employers has been working with 92 NHS organisations to support their work to retain staff.
"Above all, we now need certainty for European economic area nationals in health and social care, and an immigration system that complements domestic efforts - this will help ensure we have the staff required to provide first class care in the 21st century."
Commenting on the report, Dr Mark Holland, of the Society for Acute Medicine, said extra pressure on "overworked frontline staff" to meet targets needed to be eased.
He added: "This data shows it is high time we saw steps taken to stop disincentivizing staff - salaries must be fair, working conditions must be safe and sustainable and clear career pathways must be in place."