The study which interviewed more than 1,000 workers found that men are more likely to come in to work sick; 54% of men never take a sick day compared to 45% of women.
There is a large difference between younger and older workers, the survey revealed. It showed that three-quarters (78%) of 16-24 year olds feel pressured to come into work when ill compared to less than a third (30%) of those over 55.
Additionally, a third (31%) feel expected to carry on working from home when we are sick.
The report also found that bad management is causing stress at work for half (47%) of all workers, and long hours are causing work place stress for over a third (37%) of us.
Bullying from colleagues affects one in five workers (19%, and four in ten (42%) said an overly heavy workload was affecting their well-being at work.
Steven Kirkpatrick, managing director at Adecco Retail said: "The findings from the survey are surprising. With almost half of us feeling pressurised to come into work when ill, there are millions of workers at the office when they should really be at home.
"We found that ill workers are much less productive (most workers (61%) said they were up to 50% less productive). We advise ill workers to stay at home and suggest employers, for the good of their whole team, encourage those with illness to rest and recuperate.
"Stress at work is also something employers need to be aware of. Long hours, bullying and bad management are causing stress for large numbers of British workers."
Kirkpatrick added: "This in turn leads to days off. In order to keep the financial implications of sick days down to a minimum, employers need to address these issues head on to ensure an engaged and happy workforce."