Mario Sergio Ortiz Vallejos (28 January 1936 – 2 May 2006 in Santiago, Chile) was a Chilean footballer who played as a midfielder.

[1] Ortiz played club football for Palestino and Colo-Colo, where he won league titles in 1960 and 1963.

[1] He played for the Chile national football team in the 1962 FIFA World Cup, where he played as a midfielder, as Chile achieved a third-place finish.

[2] On 6 April 1965, Ortiz was one of the constituent footballers of SIFUP [es], the trade union of professionales footballers in Chile, alongside fellows such as Efraín Santander, Francisco Valdés, Hugo Lepe, among others.

[1] This biographical article related to a Chilean association football midfielder is a stub.