There were fears Jose Mourinho's return to Stamford Bridge could affect a transfer which has beeen lined up for weeks.
But a statement on the Chelsea website confirmed the deal will go through subject to Schurrle passing a medical and agreeing personal terms.
The statement read: "Chelsea Football Club and Bayer 04 Leverkusen have reached an agreement for the transfer of André Schürrle, subject to the completion of legal documentation and related matters, including personal terms and passing a medical."
The 22-year-old will officially go down as the first signing of Mourinho's second spell as manager.
A statement from Leverkusen announced Schurrle's departure in conjunction with the signing of Hamburg's South Korea striker Heung-Min Son.
Director Wolfgang Holzhauser said: "We have made it clear from the beginning that Andre Schurrle's departure would only be possible only if we found an adequate alternative.
"We have now found this alternative by signing Heung-Min Son and thus, in our view, there is nothing to stand in the way of Andre Schurrle's move."
Son's arrival on a five-year contract comes after Mourinho blocked the possible departure of Chelsea's Belgium international Kevin De Bruyne in part-exchange for Schurrle.