Those Kardashian girls love their workout clothes!

Kourtney and Khloe Kardashian looked super sexy running errands around Los Angeles on Thursday. Both gals donned some cut-out, sheer workout leggings that showed off their fit forms.

Kourt paired her leggings with grey crop top and running shoes -- while she dropped daughter Penelope off at dance class in Beverly Hills. Khloe, who has been highlighting her streamlined frame as much as possible, took her slim bod' to the gym in the AM. Khloe left the gym with wet hair and wearing a leather coat. We guess she wanted a little rock 'n' roll with her work-out wear!

Clearly both of these gals want people to notice their tight frames -- but who could blame them?! These gals look great!