The world's second largest brewer, which is still family owned, said it would sell 21% of its shares in an initial public offering (IPO) on the Euronext exchange in Brussels on 1 December.
The shares would be priced in a range between 30 and 38 euros a share, implying proceeds of 2.6bn-3.3bn euros.
The funds released by the share sale will be used to help finance acquisitions made in the UK earlier this year as well as future growth, Interbrew said.
"Expansion on the international level is vital for our company," chairman Paul De Keersmaeker said.
"We intend to take advantage of every opportunity that arises."
Competition review
Interbrew, which sells 180 brands in 110 countries including its flagship Stella Artois lager, earlier this year bought the UK brewing operations of Bass and Whitbread for a total of £2.7bn.
The £2.3bn Bass acquisition is still the subject of a review by UK competition authorities but Interbrew said it would proceed with the IPO anyway.
"There would be greater difficulty for the company to await the outcome of the findings than proceed," chief executive Hugo Powell said.
The Competition Commission is due to announce its verdict by 6 January 2001.
Investors underwhelmed
Interbrew said its IPO price was at a modest discount to rival Heineken.
But investors were underwhelmed initially, saying the issue looked expensive in light of the continuing UK investigation.
Shares would only be attractive at the low end of the price range, they said.
Interbrew's flotation will be by far Belgium's largest, beating the 1.7bn euro flotation of photography and technology firm Agfa Gevaert last year.
The sale will place a market value on Interbrew of 12.6bn-15.9bn euros.
Announcement of the IPO came as Interbrew announced net profit up 17% to 122m euros in the first half.