Nigel Farage claimed the Government viewed households where one parent stayed at home to look after children as an "economic enemy".
The comments came after the chancellor said stay-at-home parents had made a "lifestyle choice" as he explained why they would not qualify for a new scheme which will help two-earner households with an income of up to £300,000 meet childcare costs.
Nigel Farage is defending 'traditional families'
The childcare vouchers, available to parents earning up to £150,000 each, will offer support from 2015 to families where both parents work as part of a £1 billion-a-year package of Government help with nursery bills.
But writing on The Telegraph website, Farage said offering the vouchers to two-income households while "dismissing" those with one working parent "shows contempt for more than a million families who opt for the more traditional child rearing structure".
He said: "Recent nonsensical Government policy seems to suggest that the real economic enemy to the coalition isn't the failure to cut red tape and empower small and medium sized businesses, but seems to be the concept of the traditional family, where one parent (of whatever gender - after all over a million households now have the woman as the main bread winner) goes out to work while the other brings up the children."."
Farage added: "To have a Conservative Government leading a charge against marriage and the family and using taxes to act as their vanguard in this work seems to me to be betraying the very foundations of our society.
"It will be expensive, destructive and at very best a fiscal sop to the clamour from the modernist ideologues that infest Westminster."
The Ukip leader said married couples should be allowed to swap their tax allowance so that they one parent could stay at home "without suffering a massive financial hit".
Osborme has indicated that measures to recognise marriage through the tax system can be expected in his Autumn Statement later this year.
The Prime Minister has come under pressure from Conservative backbenchers to fulfil an election promise to offer tax breaks to married couples, but there was speculation that he was being held back not only by opposition from Liberal Democrat coalition partners but also by a lack of enthusiasm from the Chancellor.
At the time of the 2010 general election Cameron's party promised a transferable tax allowance worth around £150 to married couples.
Liberal Democrat leader and Deputy Prime Minister Nick Clegg ridiculed the proposals as ''patronising drivel that belong in the Edwardian age''.