Across the UK there are an estimated 2.4 million 'sandwich carers', says Carers UK.
The report claims that without support and flexibility at work, and affordable and accessible care services, these families can face a real struggle to juggle work, childcare and eldercare.
The report shows that of those who continued to work, one in five (22%) found their jobs suffered through stress, tiredness and lateness. One in eight (13%) had reduced their hours and 7% had to take a less qualified job.
It also claims that 'sandwich carers' found that a lack of suitable eldercare affected their ability to work (20%), with 18% saying finding suitable childcare was the issue. The same proportion (18%) cited childcare and eldercare costs as having an impact on their ability to work.
Heléna Herklots, chief executive of Carers UK, said: "An ageing population means that caring for older or disabled loved ones is inevitable for all our families.
"Workplace and care services must catch up with this reality of family life. As the costs of childcare place a real strain on families' ability to work, this research shows that finding affordable, good quality and flexible care for older parents or disabled loved ones is every bit as much of a challenge to families trying to juggle work and care."
Caroline Waters, director, people and policy, for BT Group and chair of employers forum, Employers for Carers, said: "Employers are seeing increasing numbers of key staff forced to give up work because the support they need to combine work and caring for ill or disabled loved ones just isn't available when they need it.
She added: "Demographic change means that increasingly, caring for older or disabled loved ones coincides with childcare. This poses new challenges to the productivity and economic activity of the nation, with businesses risking the loss of skills and talent and the significant investment it represents, if support at work and local services are not available to enable families to juggle work and care effectively."
The online survey was conducted in October 2012 and surveyed a total of 1,009 people who cared for at least one dependent child under the age of 18 and an older or disabled adult at the same time.
