I usually size down for shapewear, but I ordered a Large based on Cupid's fit guide (Waist 29-30", Hips 39-40"). The brief looked very small when I got it, but I could put it on without much difficulty. To my surprise, it was indeed true to size. It has very good control, comparable to another brand that costs a few times more. The Back Magic panel is amazing and kept the brief from riding down. Highly recommended!