Onex Investor Conference Webcast

Market Wire, September, 2007

On Wednesday September 26, 2007, Onex Corporation (TSX: OCX) will be webcasting live its Investor Conference. The conference includes presentations by the Onex management team on Onex and certain of its operating companies. These presentations form part of our continuous disclosure practice and will focus primarily on Onex' businesses acquired in 2007.

To make these presentations accessible to all Onex shareholders and interested parties, the presentations will be webcast live over Onex' website at www.onex.com commencing at 9:30 a.m. It is planned that the presentations will end in the early afternoon. For those who are unable to view the presentations live on our website Wednesday morning, a recording of the presentations will be available beginning on Friday September 28, 2007 on our website.

Onex makes private equity investments through the Onex Partners and ONCAP family of Funds. Through these Funds, which have third-party capital as well as Onex' capital, Onex generates annual management fee income from third-party capital and is entitled to a carried interest on that capital. The third-party capital under management currently has a value of approximately $5 billion. Onex also has a Real Estate Fund. Onex' operating companies generate annual revenues of $33 billion, have assets of $37 billion and 227,000 employees worldwide. Onex shares trade on the Toronto Stock Exchange under the stock symbol OCX.

For more information on Onex, visit its web site at www.onex.com .

Onex' security filings also can be accessed at www.sedar.com .

Contacts: Onex Corporation Donald W. Lewtas (416) 362-7711 Website: www.onex.com