Natalie Bond, 33, was taken to hospital after falling ill in the early hours of Sunday at the Mint Club in the city centre.
Police were called by paramedics who were treating her at the scene and her death was confirmed a short time later.
An initial post-mortem examination was inconclusive and police are awaiting the results of further tests, to see whether or not drugs were involved.
Tributes have been paid to Miss Bond, who had an 11-year-old son, as a “real character” and a “dynamo of energy”.
DJ Alex Simmons said he was shocked and saddened by news of Miss Bond’s “terribly tragic” death.
He said: “She was always so positive, always wanting to help push our events and always danced all night.
“She was a real character of the Leeds scene. As a father, myself my thoughts are with her son and family.”
Mr Simmons, who has played at club nights in Leeds for many years, said Mint Club was “one of the best and cleanest venues in Leeds”.
He added: “People just go there to enjoy themselves, I’ve never seen or heard of any trouble.
“I have DJ-ed at every club in Leeds and it’s one of the best and safest in the city.”
Miss Bond’s friends and fellow clubbers also expressed their shock on social media.
Mathew Brockman wrote on Twitter: “No one should ever not return from a night out. Absolutley awful news. RIP Natalie Bond.”
Another friend described her as “a dynamo of energy” adding: “You were one of a kind. I’ll always remember you bouncing around kissing all your friends. The life and soul of the party. You will be sorely missed.”
Ben Gafney wrote on Facebook: “Natalie was an amazing lady, the best friend I could ask for.”
Police want to speak to anyone who was in the club at the time and has any information that could help the investigation.
Call 101 or Crimestoppers, anonymously, on 0800 555111.