International Monetary Fund chief economist Olivier Blanchard is retiring from the Fund and joining the Peterson Institute for International Economics as a senior fellow, the IMF said Thursday.

Blanchard, who took the lead IMF post in 2008 amid the global financial crisis, plans to retire from the Fund on September 30.

"As one of the world's leading macro-economists, Olivier has been on the forefront of the Fund's response to the global financial crisis, spurring a fundamental rethinking of macroeconomic policy that is still reverberating in academic and policy circles," IMF Managing Director Christine Lagarde said in a statement.

The IMF said a search for his replacement would begin immediately.

Blanchard, a native of France who has spent most of his professional life in the United States, will become the C. Fred Bergsten Senior Fellow at the Peterson Institute, a position named after the founder of the Washington-based think tank.