Chelsea midfielder Oscar gave the 2014 FIFA World Cup™ hosts a 2-0 lead going into the break in the friendly, with Real Madrid striker Kaka putting the South American giants further ahead shortly after the restart.
Russian-based Hulk added Brazil's fourth just before the hour mark with Santos striker Neymar and Lucas, set to join big-spending French side Paris Saint Germain in January, completing the 6-0 rout.
"I feel great and I am happy to be back in the national squad, to be playing with younger players," said Kaka, who was involved for the first time since Brazil's quarter-final exit at the 2010 finals in South Africa.
Iraq were keen to meet some top-drawer opponents as they gear up for their 16 October FIFA World Cup qualifier against Australia in Doha.
Brazil fitted the bill nicely, particularly as they were otherwise free in an international week having already qualified as hosts for 2014.