http://www.gigabyte.com/products/product-page.aspx?pid=4150#sp
"2-way CrossFireX™ multi-GPU support"
It's also explained in your motherboard manual.
Other points:
- Whether Crossfire is a good idea is a separate issue (micro-stutter etc).
- Your CASE must fit the cards
- Your PSU must have sufficient 6-pin/8-pin cables and Power for the cards .