The Serie A league leaders had announced earlier on Monday that the Portuguese flanker had been omitted from their Champions League squad for the remainder of the campaign.
He had joined for 18.6 million euro ($23.90 million) from Porto in September, but had a dreadful start to his Inter career and was heckled by his own fans during the 1-1 home draw with Torino on Sunday.
A statement on Chelsea's official website read: "Chelsea Football Club is delighted to announce that we have signed Inter Milan winger Ricardo Quaresma on loan until the end of the season. The Premier League have confirmed the deal.
"Quaresma joins us as the sixth Portuguese player in the first team squad, following the summer arrivals of José Bosingwa and Deco, who have also worked under manager Luiz Felipe Scolari at international level.
"The 25-year-old winger can play on either flank, with his qualities of speed and finesse a regular problem for opposing defences."
The former Sporting Lisbon, Barcelona and Porto man is no stranger to Stamford Bridge, having played four times as a Porto player against the Blues, twice in 2004/05 and twice again two years later.
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