On 15 January 2008, Chelsea confirmed that the club had agreed terms with Lokomotiv for Ivanović's transfer subject to the agreement of personal terms and the passing of a medical, having beaten competition from the likes of Milan, Ajax, Juventus and Internazionale for his signature. Though the transfer fee hadn't been disclosed, it was speculated to be in the £9 million range. Lokomotiv Moscow announced the transfer fee for Ivanović was €13 million (£9.7 million). According to the club, the transfer was the largest in Russian football history. Ivanović signed a three-and-a-half year contract with Chelsea the following day. He was given the number 2 shirt. he has scored 6 goals so far for chelsea and he is also known as a ROCK at defence

Despite the substantial price tag, Ivanović did not make a first team appearance for Chelsea during the 2007–08 season under manager Avram Grant. The reason given by the club was a lack of match fitness as a result of the Russian league season's conclusion several months before his signing. However, he did play twice for the Chelsea reserve side.