The CIPD's Focus on Caring at Work report found a third (34%) of employees have some form of caring responsibilities, with only 20% citing children. However, 12% cite relatives, 6% their partner, and 2% a friend.
The survey also shows there is little difference between the sexes in their caring responsibilities, with 36% of women in this position and 33% of men.
Focusing purely on childcare, 72% of mothers and 43% of fathers have changed how or where they work to play a more active role in their children's upbringing.
Almost a third of working parents (31%) report they have worked flexibly to become more active parents, 28% have worked shorter hours and 23% have worked from home. But 16% have gone as far as changing their jobs to become a more active parent
Ben Willmott, CIPD senior public policy adviser, said: "The proportion of people having to balance work while caring for their partner or spouse, parents, and other relatives will increase as life expectancy continues to rise and as people work longer to save for retirement.
The CIPD has called for the right to request flexible working to be extended to all employees, rather than just parents, by 2013.
Willmott added: "This is not about employers putting the interests of employees before the business, it is just about them seriously considering whether they can accommodate flexible working requests in order to recruit and retain a diverse workforce.
"The survey suggests that the majority of employers are already providing flexible working options to allow working parents to play an active role in the upbringing of their children. Employers that don't provide flexible working options for working parents risk losing valuable employees.
"But our survey also indicates employees with other caring responsibilities such as ageing or sick parents and partners will increasingly expect the same sort of work-life balance opportunities as working parents."