The 2006 IRB Nations Cup was the first edition of the international rugby union tournament, a competition created by the International Rugby Board. It pits the "A" Teams of the stronger (Tier 1) rugby nations (Argentina Jaguars and Italy A) against some of the Tier 2 and 3 nations (Romania and Russia). The tournament took place between 13–24 June at Estádio Universitário in Lisbon, Portugal. Argentina Jaguars were the overall winners.