The warning comes from the Professional Association for Childcare and Early Years (Pacey), as it launches its Inquiry into Childminding in the 21st Century.
It hopes the inquiry's feedback from "childminders past, present and future" will help to reinvent the profession for this century.
The charity claims: "The ongoing decline in the number of registered childminders in England and Wales means that childminding is in danger.
"If the decline in England continues at the current rate, we will lose another third of childminders by 2027 - a total loss of two- thirds of registered childminders since 2012, drastically reducing the choice available to families.
"Ultimately, we could have no childminders left by 2034.
"If things continue as they are, in just a few years, most families will not be able to choose this high quality, flexible form of childcare."
Broadly the reasons are known for falling popularity of the profession, including lack of professional status, low incomes, and too much paperwork, said Pacey.
But with the help of University of Plymouth researchers, it wants to look at this in more detail, as well as why even fewer are choosing to register.
Analysis of Ofsted data shows that the number of childminders leaving the profession annually in England has remained in consistent decline each year, but that the number registering has declined significantly.
Research shows that childminders benefit children's communication, social and emotional development.
Liz Bayram, Pacey's chief executive, said: "We know how much childminding is valued by the families who use it and we want to ensure that future generations can choose home-based care.
"But, despite efforts by governments and regulators to ensure current childcare policy and regulation accommodates registered childminding it continues to decline.
We know there are many reasons why people are leaving childminding - lack of professional status, low incomes, too much paperwork - but we don't know as much about why fewer people are choosing to become childminders in the first place.
"No doubt some of the issues will be the same, but there is very little evidence on trends in childminder recruitment."
Chair of Pacey Jane Comeau, appealed to anyone involved in childminding, including those who have left and those who are considering registering, to take part.
She said: "We think childminding needs to be reinvented for the 21st Century and we want to hear your ideas and views on what's great about it and what needs to change to attract future childminders.
"Is the joy of working with children the biggest attraction? Or is it the independence that comes with running your own business? Does the name "childminder" put you off?
"If you could change anything about childminding what would it be?"
Pacey's board will be reviewing the charity's long term plans late this year and the inquiry will feed directly into the decisions it makes, added Comeau.
The inquiry will open with a national survey, and alongside this, social media discussions and focus groups are also planned Local authorities, parents and carers, employers and policymakers are also encouraged to take part.