Warner Music said it had carefully looked at the offer, but decided it didn't benefit shareholders.
The rejection came just 24 hours after EMI had given its $28.50 a share offer to Warner.
"This is disappointing, as we believe the logic for combining the two businesses is compelling," said Lorna Tilbian, an analyst with Numis.
If the two companies had merged, the combined company would have held about 25% of the total recorded music market, based on figures from the International Federation of the Phonographic Industry.
The Warner label has many top-selling acts including Madonna and James Blunt, while on EMI's list are Coldplay, Robbie Williams and Norah Jones.
