The Scottish Government announced that women under 40 can have three treatment cycles instead of two from April 1.
Older women aged between 40 and 42 will be offered one round if they fit certain criteria.
It means Scotland will have the most generous IVF system of any country in the UK.
The NHS is not here just for life-threatening or life-changing conditions
The shake-up is expected to cost the NHS about £1 million a year.
Public health minister Aileen Campbell today defended the spending amid pressure on accident and emergency departments and repeated failures to hit waiting time targets.
She told BBC Radio 4's Today programme: "We have always had a commitment towards ensuring there is as equitable access to IVF as there possibly can be and we had a number of recommendations presented to us that we accepted from the national infertility group.
NHS Scotland will now offer three rounds of IVF treatment for women under 40
"One of these included ensuring that couples could get access to three cycles of IVF. That is today what we are taking forward."
The SNP minister insisted money had been "put aside" to fund the IVF programme.
Pressed how she squared this with other NHS funding demands Ms Campbell replied: "We have got a fairly strong record across Scotland on our NHS.
"Some of our A&Es have outperformed the lion's share of England's A&Es.
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"We are outperforming A&Es across the UK and have done for some months.
Scotland will have the most generous IVF system of any country in the UK
"We have good investment levels in the NHS and we have record numbers of staff."
The National Infertility Group recommended the changes to the Scottish Government last summer.
It will make Scotland the IVF capital of the UK, going further than England, Wales or Northern Ireland.
Women receive two cycles in Wales and one in Northern Ireland. In England, childless couples face a postcode lottery, with campaigners warning fewer than one in five clinical commissioning groups offers three full cycles of NHS-funded IVF.
Until now those with a child from a previous relationship had been denied NHS treatment
The National Infertility Group recommended the changes last summer
Scots previously forced to go private after two cycles of IVF will save up to £5,200 for their third attempt.
Ministers are also pressing ahead with lifting a ban on couples who already have children.
Until now those with a child from a previous relationship had been denied NHS treatment.
Ministers have gone against the advice of experts in continuing to allow women fertility treatment over the age of 40 and up to 42.
IVF at 71 Fri, August 26, 2016
Max and Samantha Delmege discuss their desire for a baby and having IVF at 71 on This Morning.
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Max and Samantha Delmege are undergoing IVF – Mx is 71 years old
This was despite concerns that the success rate was not high enough for this age group.
Susan Seenan, the chief executive of the charity Fertility Network, said the annoucement was "tremendous news".
She told the BBC: "The NHS is not here just for life-threatening or life-changing conditions.
"The NHS is here to treat people who have a medical condition, a medical need, and if there's an effective treatment to offer them then that's what they should be able to access. And that's what the government has recognised."