The study, encompassing data from over 700 UK employees, was carried out by ICM. It found that 30% see poor workplace wellbeing as a reason for moving employers.
A further 26% said it would affect their thinking on long-term employment, with 21% saying poor wellbeing made them less motivated and productive.
Older workers value provisions for their welfare more than the younger generations. Almost three-quarters (74%) of 45- to 54-year-olds see flexibility and support through ill health as a priority when choosing an employer, compared to 66% of 18- to 34-year-olds.
SMEs performed significantly better than large corporates, with only 26% of employees reporting working conditions are 'adequate or poor', compared to 41% of bigger companies.
Women have more concern over wellbeing than men, with 42% reporting their employers did not provide good workplace conditions, compared to 30% of men.
Unum HR director Linda Smith told HR magazine the key to employee wellbeing is to "acknowledge that different groups have different expectations and needs of an employer." She added that some businesses are behind the curve when setting up workplaces for women as well as men.
"The modern workforce now contains more women than ever," she said. "Many businesses have failed to keep up with the changing demographic, meaning that existing wellbeing strategies can lean more towards a male-dominated workforce."