They say they plan to help would-be parents pay for one cycle of in vitro fertilization for all forms of infertility starting early next year.
But the province won't cover the costs of drugs and other services associated with IVF which can cost thousands of dollars.
Health Minister Deb Matthews wouldn't say exactly how much of the IVF costs will be covered, but estimates Ontario will pay out $50 million annually once the program is fully implemented.
She says the government hasn't decided yet whether it will offset the costs through a tax credit or through the Ontario Health Insurance Plan.
The Liberals made an election promise in 2007 to make fertility monitoring available earlier in life and make treatment "more accessible and affordable."
Couples struggling with infertility say they've had to spend tens of thousands of dollars for drugs and treatments.
Matthews says some infertile women turn to less effective and more dangerous alternatives to try to get pregnant, which can significantly increase the risk of multiple, pre-term births and severe medical and developmental problems.
She says she'll establish an advisory body for recommendations on how the Liberals could implement the program.
It will also advise the government on ways to best to promote safety, such as single embryo transfer to reduce the rate of multiple births.
The New Democrats had IVF funding as part of their last campaign platform. Thursday's announcement by the minority Liberals comes ahead of their spring budget, which would lead to an election if defeated by the opposition parties.
Quebec became the first jurisdiction in North America to pay for fertility treatments in 2010, including the cost of drugs, for three to six IVF cycles.
Manitoba offers a tax credit to cover part of the costs to a maximum of $8,000 a year.