Elmer Funke Kupper, who has been chief executive and managing director of ASX since October 2011, has resigned effective immediately.
Funke Kupper's decision comes as investigations into Tabcorp, a betting company he used to run, are underway over allegations of bribery.
ASX's chairman, Rick Holliday-Smith, will stand in as interim chief executive while the board looks for Funke Kupper's replacement.
"The ASX Board accepted that Elmer wanted to direct his full focus to the investigations which may be made into the Tabcorp matter – and not have them interfere with the important role of leading the ASX," Holliday-Smith remarked.
Last week, Tabcorp revealed that it was under investigation by the Australian Federal Police regarding a payment made relating to a potential business opportunity in Cambodia that the firm was looking into in 2009, although the company ultimately chose not to pursue the venture.
Funke Kupper has also today been granted a leave of absence from his board position at Tabcorp.
Holliday-Smith continued: "Elmer has demonstrated leadership and energy during his time at ASX. He hands over a stronger team and a core franchise well positioned for future opportunities."