Omar Sebastián Pérez Marcos (born 29 March 1981 in Santiago del Estero) is an Argentine retired footballer who played as a midfielder.

Peréz began his playing career with Boca Juniors in 2000, during his time with the club he was part of several championship winning squads.

In 2004 Peréz moved to Colombian side Junior where he played until 2007, with a short loan spell with Jaguares of Mexico in 2005.

Since 2007 he has played for Real Cartagena, Independiente Medellín and Club Santa Fe of Colombia.

Source:[1][2] This biographical article related to an Argentine association football midfielder born in the 1980s is a stub.