As per the deal, Extorre shareholders will receive $3.42 in cash and 0.0467 of a common share of Yamana per Extorre share.
As a part of the deal, Extorre has agreed to a C$15m ($14.6m) termination fee under certain circumstances, including acceptance of a superior proposal.
Extorre Gold Mines co-chairman Yale Simpson said, "The Cerro Moro project fits very well into Yamana’s portfolio and Yamana has both the operational experience in Argentina and financial strength to develop the project on a timely basis."
The transaction is expected to close in August 2012.
Â