Ms Vilgan's resignation yesterday ends a 27-year career at QSuper, including 18 years as chief executive.
Ms Vilgan has advised the super fund's board she will leave on 23 October 2015, and in the meantime QSuper has initiated a "formal search" for her replacement.
QSuper chairman Karl Morris said Ms Vilgan will spend the next three months working with the board and executive team to support QSuper through the transition.
"The QSuper Board and Rosemary are very committed to the continued success of the fund. We wish her all the very best for her future endeavours," Mr Morris said.
During her tenure, Ms Vilgan saw the development of QSuper via the merger of various Queensland government funds to create member accounts totalling $90 billion.
