Mario and Luigi's last name is Mario. Mario Mario and Luigi Mario. This is why they are always referenced as the Super Mario Brothers.
Yamasaki? There names are Mario Mario and Luigi Mario.
its is Mario as in the super Mario brothers. hi um no its really not that would make no sense Hey im luigis #1 fan and you're wrong Luigis and Marios last name is Gonzales so it's Luigi Gonzales and Mario Gonzales have a nice day!
Mario
mario is luigis bro
mario 3d land
Mario and Luigi's last names are, according to their creator Miyamoto: Mario. Mario Mario and Luigi Mario.
silly! its Luigis mansion
no one knows yet.
No. They're more like Mario and luigis evil twins.
check the game guide on IGN...........its on the course Big Boo's Haunt :P
This answer comes in simple terms. They are the Mario Brothers. Therefore their last names are Mario. Seriously. That's it.
marios brother is luigi and luigis brother is Mario wario and waluigi are there cousins