Osorio made his debut for El Salvador in an April 1991 UNCAF Nations Cup qualification match against Nicaragua and has earned a total of 67 caps, scoring no goals. Osorio has been a national team stalwart for over 10 years and has represented his country in 18 FIFA World Cup qualification matches over three campaigns and played at the 1991, 1993, 1995, 1997, 1999 and 2001 UNCAF Nations Cups, as well as at the 1996 and 2002 CONCACAF Gold Cups.