Conservative membership has nearly halved under Cameron
Conservative Party membership has almost halved since David Cameron became party leader in 2005.
The party says it now has 134,000 constituency members, down from the 253,600 who voted in the leadership election Mr Cameron won.
In 2012 Labour had 187,537 members while the Lib Dems had 42,501.
There has been a general decline in party memberships over recent decades, although UKIP has bucked the trend by doubling since 2010 to 30,780 members.
Conservative Party chairman Grant Shapps wants to send MPs a league table of their own constituency's standing - in order to "concentrate a few minds".
The Conservative figures were released after a campaign by the influential website ConservativeHome, which is run by former Conservative MP Paul Goodman.
Writing on the website, Mr Goodman called the release of the figures "a victory for ConservativeHome", adding: "But, more importantly, it is a victory for good sense - and the party's interests."
The party's previous refusal to publish the number fuelled speculation that it had fallen below 100,000.
New technology has led to parties communicating with supporters - who may not be members - directly through emails and text messages.
Conservative MP Douglas Carswell, who has doubled membership in his Clacton constituency, wants the party to bring in £1-a-year supporter status so people can register online as a supporter and have some say in policy development.
Labour Party vice-chairman Michael Dugher said the figures suggested that "under Cameron, the Tories are becoming an endangered species".