The prime minister acknowledged that - despite the increase at the 2010 general election - there are "not nearly enough" female Tory MPs.
And he said it is not enough for institutions simply to allow women to compete for jobs, without taking action to overcome other barriers to female success.
He revealed that his wife, Samantha, has pressed him for action on the issue.
"My wife likes to say that if you don't have women in the top places, you are not just missing out on 50% of the talent, you are missing out on a lot more than 50% of the talent - and I think she probably has a point," he said.
During a visit to Unilever's headquarters in Mumbai, Cameron was asked by a female employee if Britain had anything to teach India about opening up opportunities to women.
He replied: "We still have a long way to go. If you look at the top businesses in Britain, there still aren't nearly enough women in the boardroom.
"If you look at politics in Britain, there aren't nearly enough women around the Cabinet table.
"I think in every walk of life, whether the judiciary, politics or business, there is a lot further to go.
"My own view is it isn't enough just to open up and say we will treat everyone equally, when you are starting from such a position of disadvantage.
"Companies, political parties and other organisations need to actively go out and encourage women to join in, to sign up, to take the course, to become part of the endeavour.
It would seem that Cameron's problems with the female electorate run deeper than just women in top jobs.
Cameron has also faced criticism for running an "Etonian clique" at the heart of his government that shuts out women.
Dame Helen Ghosh, the former permanent secretary at the Home Office until she announced her retirement in August, told students at Cambridge University last November that the prime minister's inner circle was too hard to break into.
She said: “If you look at the current government, not necessarily back to the Bullingdon Club days, but Cameron, it is true, it is well known, has a clique, a network of friends — the friends he made at school, friends he made at university."
In Mumbai, Cameron stressed the progress the Conservatives had made and how much was still needed.
He said: "In terms of my political party, before the last election we only had 19 women Members of Parliament. We have around 50 now.
"We have made a big change, but it is only 50 out of 300, so it's not nearly enough, so we need to do more."