I originally ordered an XXS, as I am petite and the sizing chart recommended I go smaller. However, when I received the leggings, though they fit in size, every time I bent my legs - from walking up stairs or squatting - the fabric would stretch and turn white, taking away from the sleek black fit of the pants. This is probably due to white lining the inside of the leggings. Regardless, even though these fit well (I ended up returning them and getting a size bigger), I still have the same issue when the fabric stretches. I like how they fit, and I think it's too late to get a refund for the pants, so I'll just wear long T-shirts and hope for the best!