The Portuguese has never indicated a wish to leave the Bernabeu but that has not deterred colourful Berlusconi, often accused by opponents of making outlandish bids for political popularity, from making the pledge on Italian TV late on Monday.
"If we win the scudetto then the next transfer window will see us add one or two great players, and one of those could be Ronaldo," Berlusconi said.
"If we were able to add Ronaldo to our squad I think it would please everybody. Sometimes dreams come true."
Milan are three points clear in Serie A with six games left as they bid for a first scudetto since 2004.
Berlusconi reined back spending during the global economic crisis but eased the purse strings at the start of this season with Zlatan Ibrahimovic arriving from Barcelona, although the Swede's recent disciplinary problems have tested his patience.
"Did I throw my money away?" Berlusconi was quoted as saying by Italian media after forward Ibrahimovic was sent off for swearing in the 2-1 win at Fiorentina, triggering a second straight ban.
Several ageing Milan players reach the end of their contracts in the close season including Clarence Seedorf and Andrea Pirlo but the owner said he hoped both players would stay.
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