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).

[1] The tournament took place between 13 and 24 June at Estádio Universitário in Lisbon, Portugal.

Argentina Jaguars were the overall winners.

The competition was played over three match days, with two matches played consecutively on each day.