The SNP's membership has now fallen to just over 72,000, the party has confirmed.
Candidates Ash Regan and Kate Forbes had demanded to know how many members were eligible to vote in the contest to succeed Nicola Sturgeon.
The party initially refused to do so, but has now told the candidates that it has 72,186 members.
The SNP's membership hit a peak of 125,000 in 2019, but had dropped to 85,000 by the end of last year.
Its Westminster leader, Stephen Flynn, told the BBC earlier this week he had "no idea" how many members the party had, but that "I think the last time I heard it was about 100,000".
Ms Forbes' campaign manager, Michelle Thomson MSP, said she was pleased that "common sense has prevailed" and the membership numbers had been published - but that the "alarming drop in members shows that the party needs a change in direction".
Get things done
Ms Regan issued a statement that said only: "I get things done."
Her campaign questioned on Twitter whether the big drop in membership - which it linked to the government's controversial gender reforms - was a reason for Ms Sturgeon's resignation.
Ms Regan also repeated her call for an independent observer to be appointed to oversee the leadership election.
The SNP's national secretary, Lorna Finn, wrote to the candidates earlier on Thursday in an attempt to address their concerns about transparency.
A spokesperson for the party said: "All three candidates were successful in parliamentary selection contests using exactly the same voting system and independent ballot services firm.
"The national secretary has again confirmed all necessary safeguards are in place to protect the integrity of the ballot."
No tangible evidence
The third candidate in the contest, Humza Yousaf, said his two rivals had produced no tangible evidence that would throw the integrity of the election process into question.
But he added that it had been "a bit of an own goal" for the party not to have published the figure at the start of the process, adding: "I don't know why they didn't - they should have done and certainly if I'm the leader of the party I'll make sure they are published annually."
Mr Yousaf is widely seen as being the favoured candidate of Ms Sturgeon and the SNP hierarchy as a whole, with Ms Regan previously claiming that the party HQ was "bussing in" his supporters to hustings events.
Ms Regan has also questioned the role of SNP chief executive Peter Murrell - Ms Sturgeon's husband - in the leadership contest, saying it was a "clear conflict of interest".
Her campaign had also said it had concerns about votes from deceased party members or those who have allowed their membership to expire.
An open letter sent on behalf of Ms Regan and Ms Forbes to Mr Murrell had called on him to clarify how many "paid-up" members the party has, and the number of digital and postal voting papers that have been released.
No crisis
Ms Sturgeon denied her party was in crisis and said she had "100% confidence" in the process, as she left her penultimate First Minister's Questions yesterday.
Scottish Conservatives chairman Craig Hoy said the SNP "had to be dragged kicking and screaming into even releasing these numbers".
He added: "The SNP Government are out-of-touch with the real priorities of Scotland and it seems tens of thousands of now former members have also come to that conclusion and decided enough is enough."
The leadership ballot is being managed by polling firm Mi-Voice, which the SNP has used for internal contests since 2013. The result is due to be announced on March 27.