Carlos Bilardo, the coach of Argentina's World Cup-winning side in 1986, has been in a Buenos Aires hospital since Thursday, local media reported.
The news was confirmed by family sources and the Telam news agency, with reports indicating the 80-year-old complained of significant discomfort and is suffering from severe depression.
Bilardo served as the national team coach from 1982 to 1990 and guided an Argentina side featuring Diego Maradona to a second World Cup triumph at the 1986 tournament in Mexico.
He was coach of Argentine giants Boca Juniors as well as Estudiantes and San Lorenzo, and spent the 1992-93 season with Sevilla in Spain.
He also had spells in charge of Colombia, Guatemala and Libya.
Carlos Bilardo is in hospital in his native Argentina