The light heavyweight matchup was first reported by The Wrestling Observer.
After winning five-straight bouts to open his career, including four-straight in the IFL, Gusmao made his UFC debut at UFC 87 in August, dropping a unanimous decision to Jon Jones.
Mendes, too, will be looking his first UFC win in the January matchup. After compiling a 14-2 record in a variety of promotions Mendes debuted in the UFC at UFC 84 in May, losing to Thiago Silva via strikes midway through the opening round.
UFC 93 features a light heavyweight clash between former UFC middleweight champion Rich Franklin and former PRIDE champion Dan Henderson and a 205-pound battle between UFC hall of famer Mark Coleman and Mauricio “Shogun” Rua.