Early in his career, Hossa represented Slovakia in two World Junior Championships, in 1997 and 1998. Also appearing in his first World Championships in 1997, tallying two points as an 18-year-old, Hossa has made seven appearances in the tournament throughout his career. Despite personal World Championship best seven-point performances in 1999, 2004, 2005 and 2006, Hossa has remained medal-less with the Slovak men's team.