"Chelsea Football Club is delighted to announce the signing of Raul Meireles from Liverpool on a four-year contract," the London club said on their website.
The 2010 league champions turned their attentions to the 28-year-old after a massive bid of 40 million pounds for Croatia midfielder Luka Modric was turned down by London rivals Tottenham Hotspur.
Chelsea's move for Meireles was almost a carbon-copy of their late deadline-day signing of Liverpool striker Fernando Torres for 50 million pounds in January.
Meireles was transferred to the Stamford Bridge club just hours after Liverpool confirmed he had submitted a written transfer request.
He was at Anfield for just over a season and made 44 appearances for the Merseyside club.
The highly-rated Meireles began his career with hometown club Aves before moving to top-flight Boavista where he spent one season before joining Porto in 2004.
He flourished at the Stadio do Dragao and helped Porto to a domestic treble in 2005/06.
Two more league titles followed in 2008 and 2009 as Meireles also established himself in the national side.
He played every game during qualifying for the 2010 World Cup and caught Liverpool's eye by scoring in a 7-0 rout of North Korea in the finals in South Africa.
After a low-key start in English football, Meireles suddenly burst into life in January by scoring five times in six games.
He becomes Chelsea's sixth signing since the end of last season, following Juan Mata, Thibaut Courtois, Romelu Lukaku, Oriol Romeu and Ulises Davila.
Keeper Courtois is spending this season on loan at Atletico Madrid while attacking midfielder Davila has agreed a similar deal with Dutch club Vitesse Arnhem.
