Nearly a third of carers are spending the equivalent of an average working week minding a loved one living with cancer.
Many spend more than 45 hours every seven days in their role as carers.
Over a fifth are also working full or part-time jobs outside the home.
"The research findings clearly demonstrate the significant time commitment involved in taking care of a loved one with blood cancer and the impact this can have on their own life with many people finding they do not have as much time for holidays, hobbies, socialising and spending time with their families," said Mary Kelly, chair of Multiple Myeloma Ireland.
"It is of the utmost importance that people who are providing this vital support for people with blood cancer, find the time they need for themselves and to ensure that they are getting the care that they need to help them during this stressful time."
The figures have been released to mark Blood Cancer Awareness Month and a new campaign to make carers visible.
Almost two-thirds of cancer carers say they receive no support on how to carry out their role, with nearly half thinking they would benefit from mental health or mindfulness training.
"We would urge people living with blood cancer and their carers to access the information videos on our website to provide them with the additional support and information that they may need.
"The Irish Cancer Society provides a specialist Cancer Nurseline on 1800 200 700 and our website cancer.ie outlines our expert cancer information and support services that are available, including our Daffodil Centres in 13 major hospitals nationwide."