An elite monster counts as two monsters of its level for encounter building and rewards.
Combined with another role (an elite brute, for instance)
Deals twice the damage of a standard monster
Lasts twice as long as a standard monster
Tip: Use one elite monster as a “mini-boss” or an otherwise notable foe.
Published in Monster Manual, page(s) 281, Rules Compendium, page(s) 288.