The study of workers with jobs in support, administration and nursing found that in 48 per cent of cases, their wages did not stretch to being able to buy items including books, a warm winter coat and new shoes.
Researchers found 80 per cent had some difficulty paying household bills, while 40 per cent could not manage to save £20 a month and one in ten had a second job.
One female employee of NHS Greater Glasgow and Clyde (NHS GGC) told the Glasgow University researchers: "I have three children in primary school and I often struggle to buy food for them, adequately heat my home and buy petrol. If it wasn't for help from my parents we would not survive."
Another mother said: "I often have cereal for dinner as the food I have, I would rather my children ate."
The survey, commissioned by the NHS GGC branch of trade union Unison, was sent to all their local NHS members last summer and 1718 (13 per cent) took part.
Nearly a third of them said they constantly struggled to pay household bills, with 11 per cent falling behind on mortgages or rent. 17 per cent were behind on council-tax bills, 15 per cent on hire purchase payments and 20 per cent on credit-card payments. Borrowing from family was common and 16 per cent of workers used credit unions. Four per cent had used payday loans.
The majority (58 per cent) said they could not meet an emergency expense of £500.
Dr Robert Stewart, co-author of the report, said such problems had wide impact: "It matters on a lot of levels. It matters for the employee about how they see themselves valued in their job."
His colleague Jeanette Findlay, a senior lecturer in economics, said she was shocked to find 48 per cent of the workers could not afford three items regarded by a separate survey as necessities, which is considered a barometer of poverty.
The necessities include books at home, a warm winter coat and new shoes. For Scotland as a whole, the proportion experiencing this level of deprivation is 28 per cent.
She said: "There is a lot of discussion about how public-sector workers should stop moaning because they are so well off. That is not the case. They have suffered real cuts long term."
The NHS staff could not look after their own health as well as they wanted. Three out of ten said they could not afford to attend exercise classes or fund all recommended dental work and 12 per cent could not buy fresh fruit and vegetables every day.
Ms Findlay said: "Here we have a group of workers who know the importance of good dental health, and they are saying they are going without it."
The gross monthly income of 31 per cent of the sample was £1040 to £1559 with a further 22 per cent earning £1560 to £2079. Some were the only earner in their home and some had children.
Matt McLaughlin, regional organiser for Unison, said the findings were a "serious wake-up call".
He said: "Unison would not be surprised that our members' standard of living has been affected by year on year of below-inflation pay rises. But we are as surprised as anyone that such a significant number of people are in work and in poverty.
"There is clear evidence of a direct link between poverty and ill-health and in particular child poverty and child ill-health."
He said people who struggle for money despite working for the NHS may feel demoralised and be less likely to go the extra mile for patients. Sickness absence could also be higher in this group, affecting service provision, he added.
Unison represents a range of NHS workers including catering staff, porters, secretaries, lab staff, nurses, radiographers and midwives.
An NHS GGC spokesman pointed out staff are paid in excess of the living wage of £7.65 an hour, but bosses are aware some staff may face financial hardship due to external factors such as the rising price of food and fuel.
He said: "The survey shows that 800 NHS GGC staff out of a total workforce of 38,000 have reported to be living in financial hardship.
"Whilst this represents only a small proportion of our workforce, the health and wellbeing of all of our staff is important to us and are committed to providing support to them."
He added that money advice schemes supported staff, and those suffering financial hardship can apply to an NHS credit union.
A Scottish Government spokeswoman said the Health Secretary has a clear commitment to NHS staff being paid at least the living wage. "We have also maintained our commitment to ensure that NHS agenda for change staff get the full one per cent pay rise with progression fully implemented, unlike the actions of the UK Government," he added.